Talk:Periodic table/Archive 6

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Refs

Lavosier.

Also, the original work, for the list see p. 291

not maybe considered for sure, but the significant probability was considered

I am still sure that in the Alternatives section the short-period table (commonly(!) used in Russia) rather than alternatives none cares about. Again, structure here. You can type in Google Images searchbar the words "таблица Менделеева" ("Mendeleev's table" in Russian; this is how it is commonly called here) and see what you get.

(WARNING: IN RUSSIAN) This isn't for use in the article, just in case: JINR wishes the name "moscovium" for element 115 (forget the IUPAC nomination, and 116 will be livermorium anyway) as it decays to dubnium (Dubna is a town where JINR is located, in Moscow Oblast). They also say that 113, 115, and 117 are the next (after 114 and 116). --R8R Gtrs (talk) 12:45, 19 January 2012 (UTC)

The French version of this article contains a lot of information on the history of the periodic table. Double sharp (talk) 03:40, 22 January 2012 (UTC
Sorry I haven't gotten to these sooner; I was looking for them on the peer review page and forgot to check here! Will implement them in a couple of days. StringTheory11 21:05, 22 January 2012 (UTC)
So should we redirect moscovium to ununpentium? Double sharp (talk) 05:51, 23 January 2012 (UTC)
No, to ununquadium. 58.187.25.137 (talk) 03:32, 26 January 2012 (UTC)
What good would it do to redirect it to Uuq? They are thinking about naming 115 moscovium, so it should redirect there, or possibly Uuh, as it was a proposed name. Personally, I vote for Uup. StringTheory11 04:39, 26 January 2012 (UTC)
I would think that redirecting it to Uup would be more accurate. Double sharp (talk) 10:43, 26 January 2012 (UTC)
Generally, I'd rather suggest leaving it for now a redlink. No matter what, this is just an intention, not even official. I bet my pants even Dubna team refers to it as "element 115" or something based on 115. When IUPAC agrees there is element 115 and the name is officially suggested, then of course.--R8R Gtrs (talk) 11:34, 26 January 2012 (UTC)
So should we delete moscovium, or leave it as a redirect to ununhexium? Double sharp (talk) 09:21, 27 January 2012 (UTC)
Roentgenium111 suggests changing moscovium to a disambiguation page with links to both Uup and Uuh. Double sharp (talk) 13:15, 4 February 2012 (UTC)

Naturals and Primordials

Section Content, line 11:

"As of 2012, the periodic table contains 118 confirmed chemical elements, of which 112 have been recognized by the International Union of Pure and Applied Chemistry (IUPAC) and named. 98 of these occur naturally, of which 83 are primordial..."

As I counted, there were 84 primordials (81 from 1 - 83 ignoring 43-Tc and 61-Pm, plus Thorium, Uranium, Plutonium).

Further, 95-Am, 96-Cm, 97-Bk and 98-Cf are products from nuclear weapons, not natural, but synthetic. So please change it.

58.187.25.137 (talk) 03:32, 26 January 2012 (UTC)

You are right on the primordials. I will change that. However, there was a discussion on WT:ELEM about Am-Cf very recently and we decided to list them as natural radio because they do occur in trace amounts in Uranium ores. StringTheory11 04:36, 26 January 2012 (UTC)
Give me source, or I don't believe. 58.187.25.137 (talk) 06:17, 27 January 2012 (UTC)
Emsley, John (2011). Nature's Building Blocks: An A-Z Guide to the Elements (New ed.). New York, NY: Oxford University Press. ISBN 978-0-19-960563-7. Double sharp (talk) 09:09, 27 January 2012 (UTC)
Then the following page needs to be rewritten: Radioisotope.58.187.25.137 (talk) 09:20, 29 January 2012 (UTC)
That page will soon be updated with data from the above book. Double sharp (talk) 10:07, 8 February 2012 (UTC)

(Outdent) Surely plutonium should not count as a primordial, per the talk above. Rwflammang (talk) 17:10, 8 February 2012 (UTC)

Its half life of 80 million years is sufficient for trace quantities of primordial plutonium (Pu that was present at the time of Earth's formation) to be still present today. Double sharp (talk) 13:15, 7 March 2012 (UTC)

Layout (mostly for self-reference)

  • Lead: Should give an overview of the rest of the article
  • History: Should explain the basics of the history
    • Precursors: Should explain previous attempts to systemize elements
    • Mendeleev's table: Should explain how Mendeleev came up with his table and why it is "better" than previosu ones
      • Further developments: Should explain modifications to Mendeleev's table after he published it
  • Contents: Should explain what is in the table
  • Organization: Should explain why the table is organized the way it is and give the names of components (e.g. groups)
    • Groupings: Should explain the different groupings as an overview (blocks, etc.)
      • Periods: Should explain the periods and list periodic trends
      • Groups: Should explain the groups and list periodic trends
      • Blocks: Should explain the blocks and list periodic trends
    • Variations: Should explain minor variants in the standard table
  • Expected future developments: Should explain how the table may be changed by future developments
  • Alternatives: Should explain alternative tables in use today
  • Notes (if necessary)
  • References
  • Bibliography
  • Further Reading (if necessary)


StringTheory11 23:55, 3 February 2012 (UTC)

Exceptional cases

After all this explanation of the reasons for the periods and groups and trends of the periodic table, do you think the subject matter will ever get around as to why OE21Sc45 has to have 3 extra neutrons to be stable, or OE25Mn55 and OE27Co59 to have 5 each? Or is the reason for that occurrence not relevant to the table due to its not being a chemical category phenomenon? What does IUPAC have to say about that? Should maybe the Physics people have their own periodic table?WFPM (talk) 01:12, 18 April 2012 (UTC)

This info is not relevant to this article. It, however, is relevant to the isotope article, so could be added there, if it isn't already. StringTheory11 02:36, 18 April 2012 (UTC)
I guess that's my trouble. After 3 years in Wikipedia, and this is the first time I've heard of the Isotope article. Thank you.WFPM (talk) 14:13, 18 April 2012 (UTC)
And please note that the article discussion about "properties" talks more about the chemical properties and associated theories, which leads one away from someone thinking of the individual atom of each element as being a real physical entity with a "primordial" (physical?) means of creation. So when one hears the name of the element, should one be thinking of the properties "en masse" of this element or should he try to individualize the properties of the individual atom? And if not here, then it is in Wiki's order of priorities to subordinate it into a lesser category of topic subject matters.WFPM (talk) 17:24, 29 April 2012 (UTC)

Atomic Radius Image

The image showing trends in the periodic table is blatantly wrong. The radius of the elements increases from top to bottom, and from left to right. The image used in the article shows atomic radius increasing from right to left. — Preceding unsigned comment added by 80.212.216.223 (talk) 20:28, 11 February 2012 (UTC)

Wanna bet? :D When you go across a period, you are adding electrons of the same shell, but since the charge of nuclei increase, the interaction forces between nuclei and electrons get higher, causing this to happen. When going down, the confusing one is the level number, as 3s shells are further from the nuclei than 2s (therefore, rNa>rLi) Not so great from the point of view of science, but should be helpful. Yours, R8R Gtrs (talk) 20:52, 11 February 2012 (UTC)
Thank you R8R Gtrs for that excellent pdf. I just was looking at Fluorine and your work there. So fine! --FeralOink (talk) 22:40, 23 February 2012 (UTC)

What is the Chemical Society?

In section 1.1 there are references to a Chemical Society. They aren't linked internally, and even after spending awhile digging through the citations, I was uncertain what it was, or where it was. It seems that there was a Chemical Society associated with some of the referenced publications in the 1850's through 1890's. These were English language publications, from the U.K. But Mendeleev was in Russia, and I also saw references to a Russian chemical society though not with that exact name. I can dig around some more find the official name of the Chemical Society mentioned here. If I find it, I will append the information to this comment and try to update the article. Or someone who knows more about this than I do should do this! Otherwise, I thought this was one of the better pages on Wikipedia. I love the periodic table of the elements. --FeralOink (talk) 22:25, 23 February 2012 (UTC)

I just replaced two occurrences of Chemical Society with the appropriate Wikilink. I made a few minor grammatical changes, a diff will make them obvious. Mostly, I changed any sentences that were broken by a colon, so that the word after the colon was capitalized. Some of the article adhered to that convention, which I believe is correct, some of it didn't, so I changed it. There were a few other things, but I'll leave that for another day. This was rather a big step, editing the Periodic table, even though minor. Incremental does it...right? --FeralOink (talk) 02:36, 7 March 2012 (UTC)
Hey, don't worry about it, it's fine to edit important articles! All of us were newbies here at one point (even this guy). You shouldn't feel shy at all about editing these articles; after all, an encyclopedia with low-quality vital articles isn't a good one at all. StringTheory11 04:34, 7 March 2012 (UTC)

Grammar cleanup required

In the section Bohr model breakdown, of needs to be removed from the phrase "of greater than" since this is grammatically incorrect.

 Done StringTheory11 23:06, 11 March 2012 (UTC)


Why no periodic table including the names of elements?

This is an encyclopedia, people who need to look at the periodic table do not already have an encyclopedic knowledge of the periodic table and what every abbreviation for every element stands for. — Preceding unsigned comment added by 86.131.29.15 (talk) 14:15, 10 April 2012 (UTC)

Good point.--Stone (talk) 17:39, 10 April 2012 (UTC)
 Done I've added a link at the top of the periodic table shown that goes to a large version (also on Wikipedia) including the element names and the atomic weights. Double sharp (talk) 15:28, 11 April 2012 (UTC)
Ugly. By wikitable and by visible result. -DePiep (talk) 21:42, 19 April 2012 (UTC)
Really, User Double sharp, I do not get (nor can find) your edits in this. -DePiep (talk) 21:54, 19 April 2012 (UTC)
I added the link in this edit. The link goes to Periodic table (large version). Double sharp (talk) 10:31, 20 April 2012 (UTC)
This edit is passable. (In general, I say our PT template overviews are below standard. In short: structure/overview/navigation/lists: bad, and this is chemistry facts ony to be presented!). -DePiep (talk) 00:42, 27 April 2012 (UTC)

{{Periodic table}}

Well, I must say: the Periodic Table environment doesn't look good here at WP. Take my main entrance pont: {{periodic table}} (singular of course). All dimensions and variants are mixed. Noone really knows if a page is a template, a standard-article (like with text), or just an incomplete element-to-be-used-in=text? Realy, a bad WP organisation. I will propose improvements. -DePiep (talk) 01:17, 27 April 2012 (UTC)

Even Barium has a clickable Periodic table in the post stamp area, while this page has a picture there. Bad quality, WP:ELEM. -DePiep (talk) 19:51, 30 April 2012 (UTC)

GAN Nomination

Just a note to say that there is a citation needed tag on the Modern quantum mechanical theories of atomic structure explain group trends by proposing that elements within the same group generally have the same electron configurations in their valence shell, which is the most important factor in accounting for their similar properties. paragraph. This will have to be sorted before the article gets GA status. AIRcorn (talk) 12:15, 9 May 2012 (UTC)

GA Review

GA toolbox
Reviewing
This review is transcluded from Talk:Periodic table/GA1. The edit link for this section can be used to add comments to the review.

Reviewer: Grandiose (talk · contribs) 19:19, 14 May 2012 (UTC)

I will be undertaking a review of this article over the next week or so, but I have some preliminary points to work on:

  • The one citation needed tag is an obvious one;
  • "While rectangular in general outline, gaps are included in the rows or periods to keep elements with similar properties together, such as the halogens and the noble gases, in columns or groups, forming distinct rectangular areas or blocks." is a real hash of a sentence. I suggest you have another go at explaining what's meant here. "Because the periodic table accurately predicts the properties of various elements and the relations between properties, its use is widespread within chemistry, providing a useful framework for analysing chemical behavior, as well as in other sciences." is better but still poorly worded.
  • The external links need to be formatted properly, some indication of where they are going to take us.
  • Could you just confirm that "Another of the most common alternative layouts is Theodor Benfey's periodic table" is supported by the citation? It would have been tempting to merely link to an example and therefore if you could possibly verify this.
    • Removed "of the most common", so  Done. StringTheory11 19:07, 15 May 2012 (UTC)
  • Could you please explain how "Calculations from the Dirac equation" is within the scope of this article;
    • In my opinion, the Dirac equation is in the scope of the article because it helps identify where the end of the periodic table may be. If we can get consensus that it is not notable, however, I would not be opposed to removing it. StringTheory11 01:46, 15 May 2012 (UTC)
      • Oh, I misunderstood it. The two subsections need to be introduced in the first part of that section, I think. The last sentence of the first part seems to be a repeat of the second section. Not particularly keen on "more accurate" unless there were literal errors in the original – it seems to me that the model has to be merely refined to produce a better result. Grandiose (me, talk, contribs) 09:16, 15 May 2012 (UTC)
  • "Note that as atomic number" not encyclopedic.
  • Reading through I'm considering requesting a copyedit or something of that sort. I think it is vital on an article of this importance to get this right: "clear and concise" must be strictly interpreted
  • "Period trends" and its subsections don't seem to do a good job of explaining the actual trends. Some good info on the definition of a group and period (although this could still be clearer). Things like "usually decreases" and "Metals (left side of a period) generally have a lower electron affinity than nonmetals (right side of a period) with the exception of the noble gases." go basically unexplained. Some words could be cut out of saying there's "a trend" as an introduction to each point – if you say something increases or decreases, one can readily infer there's a trend.
    • I'm considering splitting this up into two seperate sections: one explaining what the periods, groups, and blocks are, and one explaining the trends in them. This will take some time, so it will take me a few days to get done. StringTheory11 16:07, 17 May 2012 (UTC)

All for now. Grandiose (me, talk, contribs) 19:19, 14 May 2012 (UTC)

Images

Otherwise good. No real omissions on that front either. Grandiose (me, talk, contribs) 19:31, 15 May 2012 (UTC)

  • In the history section make sure to mention the old style of classifying the groups, the main groups ?A and the transition metal groups, ?B. Nergaal (talk) 16:21, 29 May 2012 (UTC)
    •  Done StringTheory11 23:51, 29 May 2012 (UTC)
      • Was the switch to the roman numerals officially adopted at some specific point in the past? Nergaal (talk) 02:06, 1 June 2012 (UTC)
  • "Atomic number, element symbol, and name are almost always included, and atomic weights, densities, melting and boiling points, crystal structure as a solid, origin, abbreviated electron configuration, electronegativity, and most common valence numbers are often included as well" ~ is "often" correct? I've never seen one with some of this stuff.
    • I have one with these at my house.... Changed to "sometimes included as well," so  Done StringTheory11 15:03, 30 May 2012 (UTC)
  • Ref 30 needs replacing. It just doesn't cover what is implied that it does. Very little of the last paragraph of Contents is actually supported by linking to a single periodic table which doesn't explain about isotopes. I'd be more lenient about the first paragraph of Organization but even there I thin you need some other references.
  • "(the table shown in this section shows the old American Naming System)" can't really get to it and that sort of reference tends to be deprecated because we have all sorts of users where that might not apply. Better to just explain what the old American Naming System was. If one of our images uses it, it's clearly in use.
    • Image no longer in section, so  Done StringTheory11 15:15, 30 May 2012 (UTC)
  • Could you have a look at eliminating the use of the word "through" (e.g. in "Blocks")? Although the article is in AmEng, the word isn't used like that in BrEng (and others) so if you can avoid it, that's preferable.
  • The last paragraph of "Variations" doesn't seem to list variations.I suggest renaming the section, because there isn't easily somewhere else you can put it. "Variations and other conventions", maybe?

Will continue later. Grandiose (me, talk, contribs) 08:40, 30 May 2012 (UTC)

  • I think recently some elements past plutonium were regarded as naturally occurring. Nergaal (talk) 02:18, 1 June 2012 (UTC)
  • Large parts of "Atomic and ionic radii", "First ionization energy and reactivity" and "Electronegativity" are unreferenced and this needs to be done
  • You're missing a space before "tantalum"
  • "Generally the (n+1)th ionization energy is larger than the nth ionization energy. Always, the next ionization energy involves removing an electron from an orbital closer to the nucleus." A bit unclear. Start with what an ionization energy is (in a sentence) and work from there.

Grandiose (me, talk, contribs) 08:45, 1 June 2012 (UTC)

Have a look at refs #14 and #22.
 Done StringTheory11 00:05, 12 June 2012 (UTC)
Review the wikilinking of atomic number, carbon, D-block, Einsteinium, F-block, Gallium, Noble gas, proton, and ununoctium.
 Done StringTheory11 23:58, 11 June 2012 (UTC)
Grandiose (me, talk, contribs) 21:56, 11 June 2012 (UTC)

Image update

We need to update the svg image for the two newly named elements, 114, 116.(mercurywoodrose)75.61.130.86 (talk) 01:09, 1 June 2012 (UTC)

 Done Double sharp (talk) 15:37, 13 June 2012 (UTC)

Why in the world is this protected?

Is this really a heated topic? Humanpublic (talk) 17:35, 23 July 2012 (UTC)

It has been the frequent target of vandalism. -- Ed (Edgar181) 17:39, 23 July 2012 (UTC)
Articles on high profile common topics in primary in secondary schools are particularly prone to vandalism by students and people who think they are being silly and playing a prank on Wikipedia, Sadads (talk) 18:15, 23 July 2012 (UTC)
Any request for a edit will be visible to a member of the elemenzs project and than the edit request will be answered very fast. So it is protected but it is watched closely.--Stone (talk) 20:34, 23 July 2012 (UTC)

Bumping you some relativistic-related stuff (not insisting you need it)

Hey, I found a small graph that makes easier to understand the relativistic stuff: http://www.springer.com/cda/content/document/cda_downloaddocument/9781402099748-c2.pdf?SGWID=0-0-45-1119439-p173882610

You could use a small relativity talk in the section on future, to explain why the weird things will happen. Decide yourself if you need it (bumping just in case).--R8R Gtrs (talk) 00:03, 25 August 2012 (UTC)

One book title missing

Good job adding all the references. I placed the Bibliography before the Reference section so that the complete information for each book appears before it is cited.

However one book title is missing. Ref.20 just says Myers, R. (2003). Westport, CT: Greenwood Publishing Group. pp. 61–67 without a title, and this book is not in the bibliography so the title needs to be given in the References section. Dirac66 (talk) 16:32, 27 October 2012 (UTC)

 Done StringTheory11 (t • c) 16:35, 27 October 2012 (UTC)

Janet Left Step layout

Resolved

[1] What stretch do you mean, Ds? Is it on a wide screen? -DePiep (talk) 14:45, 31 October 2012 (UTC)

Vertical. Double sharp (talk) 14:48, 31 October 2012 (UTC)
Not with me (of course). Any period specific, or were all shell notes stretching (=below each other)? -DePiep (talk) 14:51, 31 October 2012 (UTC)
Strangely it's displaying properly now! It wasn't previously when I reverted you. Double sharp (talk) 14:53, 31 October 2012 (UTC)
OK then. For future situations: in an early preview I saw the same, so I added {{nowrap}} around the widest shell numbering (period 7 or 8). -DePiep (talk) 23:58, 31 October 2012 (UTC)

Correction to "Some element categories in the periodic table"

I'm not a Wikipedian, but I usually correct spelling mistakes and other glitches I might happen to catch in Wikipedia articles. Here's one that I think is worth fixing--I would do so if the article were not protected. In the "Inner transition metal" block, actinides appear at the right of lanthanides, suggesting a periodic transition from the first group to the second. This is clearly not the case, as the rest of article clarifies. It would better in my opinion to stack the lanthanides box on top of the actinides box rather than show them side by side.

Other than that, great article! Many thanks to all who put their time in this great educational tool. — Preceding unsigned comment added by 71.6.42.66 (talk) 16:15, 30 October 2012 (UTC)

Thank you for your gracious comments, on behalf of the many contributors to this article. That is a good call about lanthanides and actinides showing side-by-side. I'll see what can be done about that. There is a little more work to do on the article itself, IMO, but nearly there. It is a good read. Sandbh (talk) 11:30, 31 October 2012 (UTC)
  1. That would mean our grand legend for our metallic backgroundcolors would look like this sandbox. Still I do not think that would be good.
  2. First: the box is a legend to describe various background colors used. If there were no subdivisions (subdivisions the legend tries to show), then we could use more simple legend lines like "  Alkali metal". But that would make the (verbose?) description of subdivisions difficult and awkward.
  3. What the legend does not say is any sequence in the metallic character. There is no arrow present. It only (should) show the meaning of the colors, not the stepping relation you mention.
  4. That "stepping relation" (going horizontally left-to-right or v.v.) is present in the periodic table itself, especially when reading per period. Note that in a period, a color can be skipped (e.g. "Metalloid" in period 6). Such a skipping is also not pointed out in the legend box. And when one reads a column, vertically, there are also sequences completely absent in the legend box. Mean checking question: how is that not a similar problem?
  5. Still, you have a very good point: the legend presentation suggests and invites to read it that way. As if there is the horizontal sequence. Such is our trained human mind. We might want to improve that. As yet, I have no solution for that. (It would be too easy to say: "What you do not see in the periodic table above, is not there"). Still, for reasons above I do not want the current sandbox idea (Lan's and Act's colors stacked in one legend column). -DePiep (talk) 08:33, 1 November 2012 (UTC)

Janet Left Step setup

Wouldn't it be more instructive if we color the Janet Left Step with block colors instead of metalllic character colors? Also, we could make it wide, i.e. with the f-block in line. That would make it sort of full width, which is all right (with me at least) if we need it to describe it simply. -DePiep (talk) 09:04, 1 November 2012 (UTC)

I changed the colours to block colours (although that makes the chemists' issue with placing helium above beryllium a bit less clear, this colouring scheme makes more sense given that the Janet table is built from a physicist's perspective). Double sharp (talk) 10:04, 1 November 2012 (UTC)
I moved the Janet table down so that it could be made wide (which I also did). Double sharp (talk) 10:11, 1 November 2012 (UTC)

mistype in "Optimal Form"

In the last section, "Optimal Form", the words "ease of" are repeated, one repetition should be removed. It currently sais "[...] in terms of ease of ease of construction [...]". --RaoulSteffen (talk) 08:48, 7 November 2012 (UTC)

Done thank you and well spotted Sandbh (talk) 11:33, 7 November 2012 (UTC)

Janet left step as a thumb

I turned Janet back into an updated thumb. Most of my reasons have already been posted but here they are again.

  1. Janet is interesting and deserves to be included but the most recent template (pretty as it was) was too big IMO, compared to the other PT images, including those of Mendeleev. Maybe in the Alternative periodic tables article, but not in this article.
  2. The location of the thumb in terms of having pictures to either side doesn't appear to be an issue to me. It looks fine on my 13.3 notebook as well as on my wide screen monitor. Then again I had to remove the clear tag to make it look OK on the wide screen. Even so, I think it looks OK without the clear tag.
  3. I added atomic numbers to emphasize the continuity (no gaps) of Janet
  4. I put back element categories so that it is easier to see what Janet does to people's common PT preconceptions, especially what happens to helium
  5. As noted, I relocated the shell filling sequence and added block notations, as per the previous good edits. (thank you DePiep)

Sandbh (talk) 05:28, 7 November 2012 (UTC)

Fine with me, except maybe for the matallic category colors. Blocks and their filling sequence is essental for LSPT, so better be priomary. Metallic bg does not help me (wih a "common perception") with the point of filling. -DePiep (talk) 11:45, 7 November 2012 (UTC)
Actually, I don't like this version. Why a picture at all? Why not clickable cells? Why no discussion here (while serious editor Double sharp approved the earlier version)? -DePiep (talk) 22:44, 7 November 2012 (UTC)

I reiserted the earlier form. If you do not like the wide form (I could agree), then plaease change the source template. This current form is an outcome of this talk, too. The fixed pictured version was not. -DePiep (talk) 22:54, 7 November 2012 (UTC)

I made it an image for the following reasons:
  1. ADOMAH was an image so I thought replace like with like. I didn't do that originally because I was having difficulties with my graphics app so I used an html table, in order to make initial progress. I suspect that had I originally posted an image we wouldn't be having this conversation. I like Janet a lot. Before I did some research I didn't think much of Janet but I now understand its impressive elegance (even though the shell filling sequence is only approximate). But this is not a reason IMHO to give it special treatment in this article. I talk about this some more in the rest of my comments.
  2. To be consistent with the format of the other supporting PTs in the article, all of which are images
  3. To reduce the amount of screen space Janet LSPT takes up, consistent with all the other supporting PTs. Janet is interesting but does not merit special treatment over and above e.g. Mendeleev short form or Benfey.
  4. To leave enough room (in future) to accomodate an image of Rayner-Canham's Inorganic Chemist's PT
  5. To facilitate the inclusion of atomic numbers without taking up more room. The continuity of atomic numbers in Janet (no gap between s block and p block) is frequently mentioned as an advantage of this form of PT.
  6. It incorporated your work to better denote the blocks, and better position the shell filling sequence
  7. To be be consistent with the other supporting PTs none of which have click throughs
  8. A click through Janet is on the alternative periodic tables (as well as an ADOMAH image). This article needs more work but is the right place IMO for these tables. Sandbh (talk) 03:57, 8 November 2012 (UTC)
I included element categories for the following reasons:
  1. To be more consistent with the other supporting PTs (standard in lead; Mendeleev short form; and Benfey)
  2. To be more consistent with the article's flavour which is about ways to show physical and chemical periodicity rather than about the shell filling sequence
  3. Blocks and shell filling sequence are useful but not essential to Janet. He designed his table on aesthetic grounds. It was only later, with the development of quantum mechanics that it was realized that his table corresponded (approximately) to shell filling sequence.
  4. To show what effect a Janet rearrangement has on periodicity e.g. metal to non-metal transition across each period is no longer evident---one reason why Janet is criticized
  5. To highlight the placement of He (a noble gas) above Be (an alkaline earth)---another reason why Janet is criticized
I compacted lanthanides and actinides because:
  1. Janet is often criticized for being too wide
  2. I found a supporting reference
I didn't discuss any of this here because I thought my changes represented an improvement, building on earlier work (as per my earlier comments).
For the above reasons, I prefer the image. Sandbh (talk) 03:51, 8 November 2012 (UTC)

Periodic table FA

Moved from Wikipedia talk:WikiProject Elements#Periodic table FA

I am planning to nominate periodic table for FA sometime next week, after my copyedit is done. Does anyone have any suggestions for the article before I nominate it? StringTheory11 (t • c) 01:42, 10 August 2012 (UTC)

Looks good, but you could mention electron affinity together with ionization energy and reactivity in the periodic trends section. And I think the trends for metallic and nonmetallic character should be mentioned.Double sharp (talk) 06:40, 11 August 2012 (UTC)
I'm going to be really busy the next two days, but after that, I'll definitely add these in.StringTheory11 (t •c) 16:17, 11 August 2012 (UTC)
I have some observations and suggestions about this article, which I'll post shortly. Sandbh(talk) 13:29, 24 August 2012 (UTC)

Lead

  • Generally OK. There is a mismatch between the sequencing of the lead (which is fine) and that of the main body of the article. In the lead the history of the periodic table follows the definition-organization-components content whereas in the main body of the article this order is the other way round i.e. the history comes first then the discussion of components and organization etc. Also, the discussion in the lead of 'blocks' is disconnected from anything tangible i.e. where are these blocks located? Sandbh (talk) 09:04, 8 October 2012 (UTC)

First systemization attempts

  • Paragraph 1. There is a comma at the end of the first sentence---should that be there? The next sentence seems to start with 'However', however starting the sentence this way doesn't make sense. There is no 'however' to Lavoisier's attempt to classify the elements---his attempt was simply followed by further developments. Gmelin deserves a little more wordage. According to Scerri (The Periodic Table, 2007), Gmelin established a rudimentary system of elements upon which he (Gmelin) subsequently based a chemistry textbook, 25 years before Mendeleev; Gmelin also coined the word triad.
  • Paragraph 2. Should say something about de Chancourtois since he published the first system of elements in 1862, via his telluric screw, showing periodicity. (also per Scerri)
  • Paragraph 3. OK
  • This section should probably also include mentions of the work of Odling(1864) and Hinrichs (1867).

Mendeleev's table

  • The first sentence refers to Mendeleev's table (1869) and that of Meyer (1870) but the supporting citation only refers to Mendeleev's table. Meyer in fact published his table in 1864, as noted in paragraph two of the previous section. The third sentence talks about the success of Mendeleev's table but does not explain what is meant by "success".

Further development

  • Paragraph 1. OK
  • Paragraph 2. The second sentence says, 'In Mendeleev's original table, each period was the same length'. However, the accompanying picture has periods of different lengths.
    • Sentence removed. Seems that it was unsourced anyways, so  Done. StringTheory11(t • c) 00:18, 4 September 2012 (UTC)
  • Paragraph 3. OK

Components
Periodic table (standard form):

  • Aluminium is not a post-transition metal.
    • Well… we have a problem here, as there is nothing else we could call aluminium. Once the proposals above on this talk page are decided on, this should be able to be fixed.  Not done for now, but maybe later.StringTheory11 (t •c) 00:18, 4 September 2012 (UTC)
I would call aluminium a p-block metal (or p-block element). Dirac66 (talk) 11:17, 1 October 2012 (UTC)
  • Astatine is better shown, on the basis of its currently known and estimated properties, as a metalloid.
    • Once a proposal is decided upon, this will be fixed as well.  Not done yet, but maybe later.StringTheory11 (t •c) 00:18, 4 September 2012 (UTC)
  • Paragraph 1. 'All versions of the periodic table only include chemical elements, not…subatomic particles…' Not so: some periodic tables include elements 0 or 00, where one or the other of these 'elements' is a neutron or a quark, depending on the particular table.
    • Footnote added, so  Done. StringTheory11 (t •c) 00:18, 4 September 2012 (UTC)
  • Other paragraphs in this section are OK.
  • more to follow Sandbh (talk) 12:23, 29 August 2012 (UTC)
Hey, wait, how about moving the review to the article talk page with a link here? (Just don't want this page dumped)? Also, may be helpful to expalin the layout evolutionhttp://www.iupac.org/publications/ci/2012/3404/ud.html --R8R Gtrs (talk) 12:52, 29 August 2012 (UTC)
Happy to move the review; is their an easy way to do so?

Organization

  • Paragraph 1. The reference to the use of 'light' and 'heavy' to refer to atomic number is somewhat confusing, since 'light' and 'heavy' are sometimes also used to refer to less dense e.g. (aluminium) and more dense elements (iron).
  • Paragraph 2. Correctly notes that 'Hydrogen is usually placed above lithium...but is sometimes placed above fluorine, or even carbon...'. Hydrogen is also sometimes placed on its own, belonging to no particular group. The paragraph goes on to mention that 'Helium is almost always placed above neon, as they are very similar chemically' but leaves unanswered the question of where helium is otherwise placed (and why).
  • Paragraph 3. 'Mendeleev's periodic tables instead used atomic weights, information determinable to fair precision in his time, which worked well enough in most cases to give a powerfully predictive presentation far better than any other comprehensive portrayal of the chemical elements' properties then possible.' This sentence would benefit from being rewritten. The opening refers to Mendeleev's periodic tables 'instead' using atomic weights but does not explain what else was being used. The sentence itself is too long and contains unattributed terms, such as 'powerfully predictive' and 'far better'. The end of the sentence refers to 'any other comprehensive portrayal of the chemical elements' properties then possible' but doesn't explain what other comprehensive portrayals were then possible.
  • more to follow Sandbh (talk) 13:11, 31 August 2012 (UTC)
Cut (in here), past (into there), and give a link (here again)?
BTW, did you ever think of FAC commenting?--R8R Gtrs (talk) 16:33, 31 August 2012 (UTC)
Sorry I haven't had a chance to get to these; I've been busy in other areas of the wiki, and haven't had much time for this. I'll get to it within the next week. StringTheory11 (t • c) 19:22, 31 August 2012 (UTC)
No drama. I'm on the busy bus too :) Sandbh (talk) 03:40, 1 October 2012 (UTC)

Groups

  • Paragraph 1. The second sentence introduces undefined terms: 'periods' and 'blocks'.
  • Paragraph 4. Needs to be rewritten since it uses circular(?) logic, i.e. group trends are explained by valence shell electron configs since these are the most important things influencing group trends.
  • Paragraph 5. Everything after the first paragraph re atomic radius, IE and EN trends is misleading since there are exceptions for each property. EN goes up, for example, not down, going down groups 10-12.

Periods

  • OK

Series

  • OK

Blocks

  • OK

Variations and other conventions

  • Paragraph 1: OK
  • Paragraph 2: Second sentence duplicates the content of the Series section.
    •  Done, by removal of series section StringTheory11 (t • c) 02:10, 3 October 2012 (UTC)
  • more to follow Sandbh (talk) 11:16, 1 October 2012 (UTC)

Periodic trends

  • Picture and paragraphs 1, 2 and 3: Several problems. The picture duplicates content set out in the earlier Periods section. Three of the trends shown in the picture—EA, metallic character, nonmetallic character—are not elaborated in the accompanying text. I have read paragraphs 1–3 many times and still do not understand their relevance. Much duplicated content. Paragraph 3 doesn't have any 'so what' value: it gives a technical explanation without explaining its significance. Major editing required across all three paragraphs.
  • more to follow Sandbh (talk) 11:35, 5 October 2012 (UTC)
Paragraphs 1-2 are relevant because they discuss electron configuration as the atomic property which determines periodic trends in large part. They should be retained in the article, although I agree that they are not completely clear and require more editing.
On the other hand, paragraph 3 serves no real purpose here. Spin-orbit coupling has only minor effects on chemical properties (as opposed to atomic spectra), and a proper explanation of these would require major additions to the article. I think we should just delete this paragraph. Dirac66 (talk) 20:58, 5 October 2012 (UTC)

Atomic radi

  • All OK but for paragraph 2 which says that, 'As the atomic number increases along each row of the periodic table, the additional electrons go into the same outermost shell...'. This is not the case with either the d block or f block elements, where extra electrons usually go into the outermost but one shell.

Ionization energy

  • Paragraph 1: OK
  • Paragraph 2: Refers to a non-existent table
  • Paragraph 3: First sentence is redundant. The rest of this paragraph duplicates the content of the last two sentences of paragraph 1.

Electronegativity

  • OK

More to follow Sandbh (talk) 23:02, 7 October 2012 (UTC)

Alternatives

  • Paragraph 1: The first sentence contains two tautologies, 1. 'iconic' + 'widely used'; 2. 'other alternative'. It is also quite a long sentence and would benefit from being divided into two or more sentences. The penultimate sentence is a bit of an orphan in the sense that it isn't clear as to why what it is talking about deserves special mention; it also introduces a new and undefined term, nucleon structure. The last sentence would be better served by showing an actual example of such a periodic table.
    •  Done, except for the example part, which I am not convinced is needed. StringTheory11 (t • c) 15:05, 11 October 2012 (UTC)
  • Paragraph 2. I'm not so sure that the LSPT is such a common alternative? The Bayley-Thomsen-Bohr periodic table, or earlier depictions thereof, it seems to me, would be a more common alternative. Regardless, if the LSPT is mentioned then there should(?) be a picture of it in this article.
    • The ADOMAH table, which there is an image of, is the modern version, so I don't think an image should be necessary. Therefore,  Not done StringTheory11 (t • c) 15:05, 11 October 2012 (UTC)
  • Paragraph 3. Presumably if reference is made to Theodor Benfey's periodic table there should be an accompanying picture?
  • Paragraph 4. Same goes for Paul-Antoine Giguère's periodic table? The last sentence should explain the relevance or rationale for omitting hydrogen and helium.
    •  Partly done, I don't want to include an image as it would make the section too cluttered, but I have added why hydrogen and helium are omitted. StringTheory11 (t • c) 15:05, 11 October 2012 (UTC)

More to follow Sandbh (talk) 02:53, 8 October 2012 (UTC)

Oh, and I'll come over with a piece of repeating propaganda: The short-period table should be in the article. All alternatives mentioned are used only in a context; some kind of specialized modifications. The short-period table is the most commonly used variant in the CIS, at least in Russia and Belarus. It is the short-period one that hangs on a wall or gets printed in the schoolbooks (or analogous university books). The usage of the "standard" variant is becoming any significant when you take it to a serious level (have no idea why, maybe too lazy to translate that too?), but only approaches fifty-fifty. It is the most common layout in a part of the world; and no mention of that? I'd rather say this is more important than all of the specialized modifications. And if it went with a picture also, it would be awesome. Maybe an element of surprise for a Western reader also.--R8R Gtrs (talk) 05:15, 8 October 2012 (UTC)
  • I think that replacement of ADOMAH with the short form of Janet is a mistake. The article reads: "Near the physics end of the continuum is Janet's Left-Step Periodic Table (1928). This has a structure which shows a closer connection to the order of electron-shell filling[80] and, by association, quantum mechanics." How short form of Janet Left Step PT is a "closer connection" to the quantum mechanics? ADOMAH Periodic Table is the only periodic table that displays primary quantum number "n" without messing up the order of the elements. On the other hand, short form of LSPT that replaced ADOMAH does not even display periods in continuous manner. Why would anybody use short form of LSPT? Just to make it fit on a page? Bad move. ADOMAH should return.Drova (talk) 22:25, 30 October 2012 (UTC)
    • Drova, I will respond shortly Sandbh (talk) 11:23, 31 October 2012 (UTC)
    • Yes, the ADOMAH periodic table is the only one that reflects the primary quantum number n of the "last electron that was added to the atom" for elements that follow the Madelung rule. However, this doesn't hold for those that don't, and besides, the primary quantum number of the outermost electrons are more important to several properties (e.g. atomic radius and reactivity), as that is precisely the period the element is in (which the ADOMAH PT does not make as clear, only connecting elements with subshells of different shells being filled but which are in the same period with guide-lines).
    • "...short form of LSPT that replaced ADOMAH does not even display periods in a continuous manner." The ADOMAH PT only does this through guide-lines, and so do the short forms of the standard and Janet periodic tables (through the asterisks). Besides, we already have the subshells filled arranged in the form of a smaller table above the LSPT, which should make it even clearer what the long form of the LSPT looks like even though we don't have enough space to put it here. Double sharp (talk) 13:33, 31 October 2012 (UTC)
If I understand this correct, the layout (readibility) issues are addressed in the current layout. To me it is instructive: first time I can understand the relation between the shell filling sequence and the PT. -DePiep (talk) 18:21, 2 November 2012 (UTC)
  • With regard to QM and electron structure of atoms, ADOMAH provides alternative algorithm of writing electron configurations, unlike any other table. See "Alternative method of writing electron configurations". {{cite web}}: Cite has empty unknown parameter: |1= (help). I would also argue that tie lines provide continuity better than asterisks.Drova (talk) 03:38, 4 November 2012 (UTC)
Drova: I replaced ADOMAH with Janet for the following reasons.
  1. When I was thinking about the organization of the Alternative layouts section I was struggling to think of a rationale for what images to show there. I could see why Benfey's table was there, this particular design being almost an icon of alternative layouts. ADOMAH I wasn't especially familiar with and could not see why it would be there given Janet was the archetypal form of this kind of periodic table. Why talk about history but not show it? Anway, while I was pondering what do about this I happened to read Scerri's reference to a continuum of PTs at which time I had my 'eureka' moment, when he contrasted Janet with Rayner-Canham's table (I will ask R-C if I can use a copy of his image or draw and include one of my own).
  2. ADOMAH suffers from being too tall, as does Janet being too wide. So I picked a compact version of Janet I found in the literature.
  3. Janet may be the next best known form of PT after Benfey. It has many references in the alternative periodic table literature (ADOMAH has far fewer).
  4. Janet is easier to draw.
  5. Even including Janet is considered to be on the fringes by some chemists, let alone ADOMAH.
The Janet LSPT now shown in the article is too big and overwhelming IMO. The compact form of Janet is sufficient, as is also the case with the thumb version of the short form PT. Sandbh (talk) 11:01, 5 November 2012 (UTC)
However, inserting the compact form of Janet makes the text of the "Alternative layouts" section sandwiched into a small column between two pictures, which doesn't look very good IMHO. Double sharp (talk) 11:06, 5 November 2012 (UTC)
  • Now I understand why you decided to replace ADOMAH with Benfey's and Janet PT's. However, I think that the reason for Benfey's PT popularity is not its value to chemists or physicists, but rather it's loopy look. I think that the basis for the selection of the alternative periodic tables should be their ability to illustrate some aspects of the periodic system better than it is done in traditional layout. One of the big things that is missing from the traditional layout is ability to illustrate clearly the electronic structure of atoms and the order of electron shell filling. ADOMAH periodic table does just that by combining Madelung rule with the periodic table. As remarked by DePiep above "To me it is instructive: first time I can understand the relation between the shell filling sequence and the PT." ADOMAH is fairly recent layout, that is why it has relatively fewer references in the literature but, should we base our selection on a basis of age and look?Drova (talk) 15:19, 6 November 2012 (UTC)

Future and end of the periodic table

  • OK

Review of the lead to follow Sandbh (talk) 05:21, 8 October 2012 (UTC)

Congrats

My compliments to those who made this page FA. -DePiep (talk) 01:22, 10 November 2012 (UTC)

Edit request on 12 November 2012

In Ionization Energy section: REMOVE "Higher ionization energies tend to be larger than lower ionization energies." I have no idea what they were trying to say there.

CHANGE "Large jumps in the successive molar ionization energies occur when passing noble gas configurations. " to "Large jumps in the successive molar ionization energies occur when removing an electron from a noble gas (complete electron shell) configuration." 99.141.189.195 (talk) 13:58, 12 November 2012 (UTC)

Done. Yes, this section was written confusingly. On your first point I have clarified that this refers to successive ionization energies of a given atom, e.g. I1(Mg) < I2(Mg) < I3(Mg). On your second point I have inserted your suggested text. Thanks for pointing out the problems. Dirac66 (talk) 16:39, 12 November 2012 (UTC)

inverted digits

The "Element with the highest possible atomic number" first refer to 137 as the problem element for the Dirac equations, then talks about 173 proton and element 173. Not knowing any of the involved math, I cannot tell whether or not this is an error, but it certainly doesn't look good. Circéus (talk) 14:38, 14 November 2012 (UTC)

It's not an error, this is actually true. I don't see why the digits are inverted; it just seems like random chance. StringTheory11 (t • c) 17:09, 14 November 2012 (UTC)
It does look suspicious. However, the reference by Philip Ball cited at the end of the paragraph mentions (element) 173 three times, so yes it is actually true in this case. Dirac66 (talk) 03:05, 15 November 2012 (UTC)
Thanks. Just wanted to make sure. Circéus (talk) 19:20, 15 November 2012 (UTC)
After you get to the end of the IUPAC periodic table at element 118, you can get to element no 120 at the end of the Janet periodic table, with both of these tables involved with 32 elements in the last extended table groupings. Then, in either case the constituents of the next level group will involve the previous 32 group spaces plus an additional 18 elements in the larger additional group, for a 50 unit addition in each level to a total content of 168 and 218 for the IUPAC table and of 170 and 220 for the extended Janet table format. See Talk:Charles Janet.WFPM (talk) 19:49, 22 November 2012 (UTC)
Both IUPAC and Janet tables classify the elements now known to exist up to 118-120. Yes, they have room for more elements, but that doesn't necessarily mean that the additional elements can actually exist. This discussion concerns the highest element which can exist (even if expanded IUPAC and Janet tables have room for more), as predicted by relativistic quantum chemistry based on the Dirac equation (not mine even if I am using his name!), which apparently is Z=173 based on some very complex mathematics. Will that prediction turn out to be true? As of 2012 we really have no idea, but it seems clear that very simple considerations based on the IUPAC or Janet tables will not help solve the problem. Dirac66 (talk) 01:34, 23 November 2012 (UTC)
173 is probably not actually the end (see the reference). But there are no predictions of chemical behaviour after element 179, except for element 184. Double sharp (talk) 02:54, 23 November 2012 (UTC)
When it comes to the existence of the atomic nuclei of the elements, the elements' chemical properties have very little to do with the situation! What is more important is the structure and associated physical properties of the individual nucleus and its relationship with its surrounding environment. That is why the knowledge about the structure and the accumulation processes become important. For example, I would think that the nucleus of one of the EE atoms of the elements 112 and 114 should be less unstable than other nuclei due to their analogy to the stability characteristics of elements 80 and 82. This would also apply to the nuclei of the elements of the elements 162 and 164 due to structural geometry considerations. I don't know how you would be able to come to that conclusion with just a mathematical analysis calculation.WFPM (talk) 17:16, 23 November 2012 (UTC)
The heavier homologues of 112 and 114 should actually be 164 (for 112) and 140 and 168 (for 114) 164 and 168 respectively, due to relativistic effects. Double sharp (talk) 14:24, 24 November 2012 (UTC)

I don't know about relativistic effects, which must be some mathematical inference effect. What I am talking about is similarities of structure such as to be able to maintain a structural balanced condition. For that reason I have to add 32 to the first increase and 32 + 18 = 50 to the second. This is due to the assumption that the additional series additions are added to the structure of the nucleus in such a manner that the parts of the structure subject to alpha particle emission possibilities are not significantly changed. What you do have in these cases, are are increased magnitude of stress due to the heavier masses involved.WFPM (talk) 18:16, 24 November 2012 (UTC)

Karol (2002) contends that gravitational effects would become significant when atomic numbers become astronomically large, thereby overcoming other super-massive nuclei instability phenomena, and that neutron stars (with atomic numbers on the order of 1021) can arguably be regarded as representing the heaviest known elements in the universe. I'm not brave enough yet to add mention of this to the periodic table article since I think Karol's argument appears to be a step too far and I haven't been able to find other authors who have cited it. OTOH he did get published in a refereed journal so maybe his article warrants mention in the PT article as a whimsical footnote. Sandbh (talk) 00:20, 24 November 2012 (UTC)
  • Karol PJ 2002, 'The Mendeleev–Seaborg periodic table: Through Z = 1138 and beyond', Journal of Chemical Education, vol. 79, no. 1, pp. 60–63
LOL! Double sharp (talk) 14:24, 24 November 2012 (UTC)
I can't imagine being worried about incremental gravitational stresses as being significant within the atomic nucleus, unless you consider the nuclear attractive strong force to be a gravitational force. What I'm talking is about the features of the nucleus that affect the ability of the accumulated nucleons to maintain their properties of spin rotation and polarity of magnetic force field that is consistent with their appropriate locations within the structure of the nucleus. Such a compatibility requirement must be that factor that causes the rapid disassociation of the nucleus of EE4Be8, since it is solved easily by nature by the addition of a stabilizing extra neutron. What is needed in this matter is a reasonably correct nuclear physical structure concept. If you try to structure the accumulation of a number of 3/8 inch diameter (neodymium) cylindrical magnets, you'll find that they have a definite set of assembly rules related to an optimum minimum size structural configuration. And the fact that their rules for best minimum size achievement coincides with the periodic sizes of the series of the Janet Periodic table leads me to believe that a study of this subject matter is worthy of consideration and discussion.WFPM (talk) 02:06, 24 November 2012 (UTC)

Number correction

Under the Layout section, it currently states that "A total of 98 of these occur naturally, of which 84 are primordial. The other 16 elements only occur in decay chains of primordial elements." Should this not say "The other 14 elements..."? 98-84=14, also there are 14 decay elements identified by their borders on the layout shown. 138.162.0.46 (talk) 16:35, 27 November 2012 (UTC)

 Done. Thank you! Double sharp (talk) 13:27, 29 November 2012 (UTC)

Edit request on 23 January 2013

i request you to change the thing in the starting. Periodic table is not only a table of chemical elements but it it also the table of gases, metals,chemicals .etc Huzaifa Irshad (talk) 14:03, 23 January 2013 (UTC)

 Not done because you are incorrect; the periodic table only contains chemical elements. Double sharp (talk) 14:55, 23 January 2013 (UTC)

Edmund Stoner contribution to the periodic table

There is no mention of Edmund Stoners 1924 paper where he proposed that the electronic configuration to explain the periodic table- following the Somerfeld work on Bohrs theory where S. introduced a third quantum number to Bohrs original scheme. Axiosaurus (talk) 12:54, 27 January 2013 (UTC)

Stoner's contribution is mentioned in the articles on Electron configuration and Pauli exclusion principle. Dirac66 (talk) 15:31, 27 January 2013 (UTC)

Chromium in antiquity

To Sandbh whose edit summary today includes the words "move Cr from dubious location in 'known in antiquity' category". The article on chromium says that "chromium oxide" was known and used as a metal coating by the Chinese over 2000 years ago, although the element was only discovered in the West in the 18th century. So there is some justification for 'known in antiquity', at least in China. Dirac66 (talk) 02:12, 12 December 2012 (UTC)

There is an excellent discussion here about the Terracotta warriors allegedly having chromium-plated weapons. My conclusion is that there is insufficient evidence for the discovery or use of elemental chromium, at the time these weapons were made. Based on what is known so far, any small amount of chromium present is accidental or possibly the result of the application of chromium compounds. Even if the latter instance was shown to be plausible, there is no evidence to suggest that chromium metal was known and recognized as such, in antiquity. I don't believe the use of a compound of an element should be counted as the discovery of that element. The seven classical metals continue to be iron, copper, silver, gold, tin, lead and mercury. It's no big deal to change the table back to show Cr as known in antiquity however I think we could do with a little more evidence. Sandbh (talk) 23:55, 13 December 2012 (UTC)
OK, thank you. On reflection I agree that we should only consider here the discovery of elements in elemental form. Otherwise we would have to say that sodium was known by the ancients because they had NaCl, and hydrogen because they had water! This would clearly make the table of discovery periods totally meaningless, so I will agree to be consistent and leave chromium out too. At least in the absence of good evidence for elemental chromium in ancient China. Dirac66 (talk) 17:28, 16 December 2012 (UTC)
The notion of "discovery of the elements" is, in fact, inconsistent. An element is said to be known since antiquity if the ancients knew an elementary substance formed of this element, although the ancients did not have the concept of "chemical element" in its modern sense. Strictly speaking, elements (kinds of atoms) and elementary substances are two different things, but even IUPAC allows calling elementary substances "elements". But in the age of chemistry, an element is often considered to be discovered when its characteristic compound (usually an oxide) was isolated. This leads to inconsistencies. For example, calcium is considered to be discovered by Humphry Davy in 1808. Magnesium is, according to various sources, considered to be discovered either by Davy or by George Black in 1755, although Black separated MgO from CaO. That is, he separated magnesium from an unknown element? Similarly, either Scheele (1774, BaO) or Davy (1808, elementary substance) discovered barium, and Davy is very rarely considered to be discoverer of strontium, although he isolated it in the elemental form. Aluminium and silicon are considered to be discovered in 1825 and 1823 by Ørsted and Berzelius, respectively. These are the years of their isolation. But beryllium and lithium are considered to be discovered by Vauquelin (1791) and Arfwedson (1815), although they isolated BeO and Li2O from Al2O3 and SiO2 and did not isolate elementary substances. With the invention of physical methods, elements became to be discovered as themselves (spectral analysis) or as nuclides (radioactivity), not as chemical substances. For example, francium was discovered by Marguerite Perey in 1939, but has never been isolated in macroscopic quantities due to its extreme radioactivity. Burzuchius (talk) 14:04, 28 January 2013 (UTC)

Element names in the table

On trying to get the element name in the PT. At WP:VPT I have started a question about layout problems. -DePiep (talk) 18:55, 28 January 2013 (UTC)

Optimal Form?

This is a good reference to show confusion. It also shows why some more complicated tables have been denied.

Fluck, E. (1988). "New Notations in the Periodic Table". Pure Appl. Chem. (IUPAC) 60 (3): 431–436

However I was recently asked when showing a table "how about a table of the Standard Model (toe). I could only ask what the person had in mind that's an endless thing to start :)

But point is the Standard Model is not for new learners and after all a good Periodic Table (that prints well) will always be what some find useful and a best place to start. — Preceding unsigned comment added by 68.100.81.124 (talk) 05:49, 1 February 2013 (UTC)

Deleted work why ??

why does "element names in table" mean a good chart should be removed for others to enjoy?

well it can at least go in Alternative Periodic Table Gallery i hope it was hard to make (though the origional is not png it's softeware generating graph that is exported to png in this case) — Preceding unsigned comment added by Sven nestle2 (talk • contribs) 08:35, 1 February 2013 (UTC)

Fuller Data with fill order

A nice chart displaying fill order and other data, works nice on iphone too:

john hendrickson periodic table, wide, color, has fill order

The same but with a newer La/Ac series layout that is easier too understand and follow with the eye:

john hendrickson periodic table, condensed, color, has fill order

errata: chart implies data is in Mathematica's (CRC 79th 1989) chem.m except Oxidation State (CRC 52nd 1972).

Sorry, these images are unreadable on my conventional desktop/laptop PCs. There are severe problems with fonts (lines too thin, thus rendering problems on Firefox), letter size and layout (spacing between words, for example). Materialscientist (talk) 08:33, 1 February 2013 (UTC)
Also, the La/Ac layout is just wrong. Double sharp (talk) 06:04, 3 February 2013 (UTC)
  1. 1 it's JPEG it's viewable stop lying.
  1. 2. if you can read the La/Ac series IS ABSOLUTELY correct. learn how to read.

STOP DELETELTING OTHER PEOPLES WORK.

the charts are fine. nicer than most. and a nice edition to those looking to print or to pan with iPhone.

You two have nothing to add but deleting other's good work with stupid comments. Get the heck out.

Where is your work to replace it? — Preceding unsigned comment added by 72.209.222.174 (talk) 00:57, 17 March 2013 (UTC)

You are essentially edit-warring against multiple other editors here on this specific page (WP:EW is forbidden behavior). Your position does not seem supported by WP:Galleries (WP:CONSENSUS overrides your preference). Your comments are not WP:CIVIL--we're all people here and deserve a polite discussion even if we disagree. As for my position, I agree with others...these tables are not so important that they should be cherry-picked into the article itself. We already have a commons link with many formats and levels of details. See also WP:IUP#FORMAT for why jpeg isn't really a good idea here. DMacks (talk) 10:12, 18 March 2013 (UTC)

"Of these, all up to and including californium exist 'naturally'..."

The above statement (in the last paragraph of the introductory section of the article) is clearly false as Tc was the first element to be synthesised; and hence produced artificially. — Preceding unsigned comment added by Combating Ignorance (talk • contribs) 23:28, 22 February 2013 (UTC)

The article on technetium says that there was a confirmed laboratory synthesis of Tc in 1936, but that it was later found in stellar spectra in 1952 and in terrestrial pitchblende ores in 1962. So it does exist naturally in very small amounts, even though the first discovery was of an artificial product. I think the article is saying that we also now know of natural sources for all elements up to and including Cf, even though some were first discovered by laboratory synthesis. (From memory, Tc, Pm, At, Fr, and all beyond U). Can someone confirm whether this statement is true, and if possible find a source? If so, we could express the facts more clearly. Dirac66 (talk) 02:03, 23 February 2013 (UTC)
Dirac66 is correct. Double sharp (talk) 15:27, 29 March 2013 (UTC)
Indeed; sources can be found in the individual elements' articles; I think Emsley, John (2011). Nature's Building Blocks: An A-Z Guide to the Elements (New ed.). New York, NY: Oxford University Press. ISBN 978-0-19-960563-7. is a common source for all elements up to Cf, which we could use here as well. --Roentgenium111 (talk) 17:33, 30 March 2013 (UTC)

Browser-dependent layout problem

There is a browser-dependent problem with the large 18-column periodic table at the beginning of the Layout section. With Mozilla Firefox it looks fine. However with Internet Explorer 8.0 (version 8.0.6001.18702) it is unreadable because many (not all) element names overlap into the next column and cover the name of the next element. For example, the names chromium and manganese are on one row only, so that chromium extends into the next column and covers manganese, and manganese extends into the next column and covers iron. Some names are broken into two columns and stay in the correct boxes, such as scandium, titanium and vanadium. Can someone fix the table so that all the names stay in the correct boxes with Explorer as a browser? Or perhaps replace all the names with chemical symbols (Cr, Mn) which are shorter and will fit into the correct boxes? Dirac66 (talk) 00:17, 15 April 2013 (UTC)

I assume it happens on this very page right? And, could you tell which screenwidth you experience this (800, 1064, 1280)? Also which Operating System (version) you have? All this could be relevant. -DePiep (talk) 00:55, 15 April 2013 (UTC)
Yes, on this page. Screen resolution given as 1024 x 768 so screenwidth = 1024. Operating system Windows XP Home edition, version 5.1. Dirac66 (talk) 02:04, 15 April 2013 (UTC)
About replacing the names with the symbols: these element symbols are already there, did not and do notr interfere with neighbours if I read you well, and already link to the right page. -DePiep (talk) 00:58, 15 April 2013 (UTC)
Yes, the symbols are there - I didn't notice them before. If we can't get the names to show properly we could just use the symbols. But since some names do display correctly, it should be possible to show them all correctly. It requires that someone look at the source code for the template and find the difference between say vanadium and chromium. Then we can put all the names the way vanadium is now, not the way chromium is now. Dirac66 (talk) 02:04, 15 April 2013 (UTC)
The names were added only last saturday, so what you found is recent. Before it was this. Thanks for the feedback, I'll take another look. -DePiep (talk) 09:38, 15 April 2013 (UTC)
OK, I see your recent edit at Template:Periodic table. The source code change appears to be similar for all elements, so I don't understand how to fix the problem so that all the element names go where they should. I think it would be best to return to the previous version with just the symbols, so that all readers can see the table properly. Readers who want to know the name of an element can just click on the symbol for that element. Dirac66 (talk) 10:52, 15 April 2013 (UTC)
You are fast! What I have changed is: cut off text when a cell is too narrow (instead of letting it overflow into the next cell). At least that prevents the ugly overwriting of text (I understand that this is correct in your IE?). Then, IE still should hyphenate "manga-nese" into two rows. That is a thing the browser should do by themselves, we cannot enforce it (unless we hyphenate all names always, which is not a nice idea). I do not get why MS IE does not do that (and does it correctly for scandium as you wrote).
Now on the desirability of adding the names. It was discussed here and here. In short, I proposed to do so because it is a primary information for PT elements (their articles are named that way for a reason). Your point that "the information is elsewhere, so just click" does not put the primary info where it belongs. Also, a user might very well be searching the other way around: "where is gold in the periodic table?". Very, very few readers are that familiar with the PT, so codes and numbers do not help them. -DePiep (talk) 11:14, 15 April 2013 (UTC)
Well, I agree that this is better. The overwriting is now gone so I can read at least part of each name. If I don't know where the elements are, I can find gold which is no longer overwritten by platinum. And if I don't know where manganese is, I can at least find mang which will help, and read the rest of the word by holding my mouse over mang. Also on Firefox the appearance is unchanged and I still have the complete name manganese in two lines. So yes, it is an improvement, thank you. Dirac66 (talk) 13:40, 15 April 2013 (UTC)
Fair enough, what you describe is how I understand the situation. These incomplete names in view is not a good thing of course, but in a tradeoff I do prefer this to leaving them out completely. I see no further changes to try, for now. -DePiep (talk) 14:52, 15 April 2013 (UTC)

disambiguation link issue...

At the top of the page, I noticed a small issue. The "For other uses, See [Example topic] (disambiguation)" link that appears over numerous articles was missing the word 'disambiguation' entirely in this one. I don't have the permissions to edit this article, since it is semi-protected. Could someone with the permissions to fix this small issue come and do so? Thanks.
(I wish I actually knew what 'disambiguation' means. )
Yea55 (talk) 16:08, 16 May 2013 (UTC)

Done. Good point, it was unclear. It now links to Periodic table (disambiguation), and says so.
btw, I changed that page name from The Periodic Table, since that is a bad title ("The" is not part of the title).
WP:DISAMBIGUATION: it means what to do when a single title (spelled alike) can have two or more meanings. See space and space (disambiguation). -DePiep (talk) 16:46, 16 May 2013 (UTC)

Meaningless phrase?

The Categories section mentions "the diatomic nonmetals, which are more or less essentially nonmetallic". Does this phrase actually mean anything? Dirac66 (talk) 22:03, 6 September 2013 (UTC)

Look in nonmetal#diatomic nonmetals. PlanetStar 19:58, 7 September 2013 (UTC)
Thanks, PlanetStar. Glad to know that you know right about that detail (we spend so much time on). -DePiep (talk) 20:48, 7 September 2013 (UTC)

The "standard" form of the periodic table

Can you change the heading to Wikipedia element project standard please- as at least that will make it clear where it comes from. IUPAC if anything is the standard. If the creeping plague of "wikipedia poor metals" moves to engulf the Zn group, it will get even worse. The only unambiguous table is one with s, p, d, f blocks and I would never bother with classifying the chemically unexplored atoms right at the very heavy end of the table- (who cares, its all speculation until there are facts!). The poor metals classification has been "contaminating" this standard P. table for a long time - rather than add to it as seems to be the momentum of a small group of dedicated editors can't we just get rid of it. Its a wikipedia invention based on a selected set of rather obscure references, in my view its a "never mind the quality feel the width" judgement that has been made. Put a wikipedia version up if you like but don't pretend wikipedia is creating a standard table!(talk) 17:31, 29 September 2013 (UTC)

Hi Axiosaurus. The expression 'Standard form of the periodic table' was intended to refer to the 18-column layout, not the colour scheme. Perhaps we could change the heading to, 'Standard 18-column form of the periodic table. The colors used in the version of the table shown here correspond to different categories of elements, as listed below in the Layout section, under the larger table.' On the question of a standard form of the PT in the sense that I think you are referring to, IUPAC has never published a standard form of PT. There is no unambigous PT. Even the ones based on s, p, d and f-blocks are ambiguous when it comes to determining where the lanthanides/actinides start and finish, and placing helium on top of beryllium is always controversial. Attempting to classify the elements at the very end of the PT is very much in the adventuresome (science-based) spirit of Mendeleev's predictions on the properties of undiscovered elements. For the record, 'poor metals’ is not a Wikpedia invention. The WP periodic table article dates from 2002. 'Poor metals' dates from before that, along with several other names for the same periodic table vicinity (between-the-transition-metals-and-the-metalloids). Sandbh (talk) 12:23, 30 September 2013 (UTC)
We could also remove the wording "standard" altogether. The other specifications we use like "wide", "compact" and "large" are layout specifics, not some definition. Similar for "extended", though that is about predicted elements so not layout. As long as we apply this systematically, it could work. -DePiep (talk) 21:36, 30 September 2013 (UTC)

Simple ambiguity in the Standard Table

This is an ambiguity that confuses the layman such as myself and not so much a technical discussion. In the layout section it states that the lanthanides and actinides fit under the Yttrium (39), but actually that alone is ambiguous as it's not clear whether 57, 71, or even all of them go under Yttrium - all are possible from a purely diagrammatic point of view. It's actually quite an effort to find out which is the correct layout. Perhaps it's not that important but the standard large layout seems to be put 71 there (and that's how each element is depicted) so I think this should be clearly explained in the layout section rather than being buried somewhere else. Macgroover (talk) 07:39, 6 December 2013 (UTC)

I just checked 10 textbooks on my bookshelf. Two general chem texts, four inorganic texts and two phys chem texts place La(57) and Ac(89) under Y(39). Two other inorganic texts place all the lanthanides and actinides there, written as La-Lu and Ac-Lr. So I think placing only Lu(71) and Lr(103) is quite rare, although I do vaguely recall seeing it occasionally.
And I doubt that there is an official correct layout, but La and Ac seems to be the most common. Dirac66 (talk) 16:14, 10 December 2013 (UTC)
But unfortunately it's also the most wrong from a physical and chemical perspective. Lu and Lr is gaining ground and only really started becoming more popular more recently; hence it's not as easy to find it. OTOH, several RS'es give very good rationales for adopting it (Sc/Y/Lu/Lr). Double sharp (talk) 16:26, 10 December 2013 (UTC)
(edit conflict) This is currently discussed at WT:ELEM. One proposal is to show group 3 to be Sc/Y/Lu/Lr and put the others in separate unnumbered column(s). 32-column and 18-column would be a 1:1 transformation. See argumentations, demos & sources there. -DePiep (talk) 16:28, 10 December 2013 (UTC)

Natural Element Synthesis in the Universe

This may not be the best place to discuss this, but it may be sufficient. In addition, I'm no physicist, nor cosmologist that could directly contribute.

It would be interesting and informative to show the latest theories for each element's natural production in the universe on each element's wiki page. E.g., Supernova nucleosynthesis and Nucleosynthesis discuss some general element synthesis methods, but having the methods for each element would be more complete. Some element wiki pages discuss the method of nuclear synthesis, but showing the exact process(es) is rare.

Examples for primordial light elements can be found in this image.

How could Wikipedia encourage and standardize this "section" for each element? Rick21784 (talk) 01:06, 7 January 2014 (UTC)

I would suggest that a better place for this comment would be at Talk:Nucleosynthesis. Dirac66 (talk) 03:18, 7 January 2014 (UTC)
Placed there now too. Thanks. Rick21784 (talk) 08:01, 6 February 2014 (UTC)

Alternatives Strongly biased.

1.)There seems to be a strong bias here to focus this article on Scerri's work. Given his apparent self-promotion across the web, and the paucity of general science community support for the more radical claims in his books, I believe this article (as well as the one on alternative periodic tables) has been warped to exaggerate the alternative tables. 2.) I challenge (but I'm a chemist, so I do not know one way or the other) the claim that the left step table is commonly used by Physicists. If it is, then where are the citations from the Physics literature? Where are the references to the Physics Educational literature. 3.) A search on Google of "Janet's Left Step Periodic Table" got < 17,000 hits. This means, essentially, it doesn't exist except in reference to Scerri's work. 4.) I do not know Scerri's work, but he is an instructor at UCLA, not a research scientist. That is, his contributions are historical, not scientific (for the most part). He seems to have been a proponent of the idea of an optimal Periodic Table. This is risible. Any thoughtful student understands that different needs can't be optimally met with a single tool. The amount of ink spent in addressing this is a red flag to me for any of his other "contributions". I apologize if this seems an ad hominem attack, I mean to suggest that this article is profoundly distorted by the inclusion of one man's non-mainstream ideas, which as far as I can see have no traction in either the educational or the science communities. 5.) The left-step table has numerous issues. It can NOT correctly be OBJECTIVELY shown to be "more congruent" (note the careful use of slippery words here) with quantum mechanics. In fact, since it is claimed to indicate the structure of the sub-shells, it is wrong time after time. Cr with a configuration of [Ar]3d5 4s1 would surprise anyone who expected that the 4s shell was well buried by the 4th transition element and who was using the left-step table. As would Cu, Nb, Mo, Tc, Ru, Rh, Pd, Ag, La, etc. (the list is too long for inclusion here). I recommend removal of the Janet's table since it is A.) Unimportant, B.) Objectively WRONG in designating electron structure and C.) Unsupported by any citations from the science community (Physics) which is claimed to support it. If it is left in, then its major flaws need be made explicit. Claiming it to be "more congruent" is deceptive, at best.216.96.79.253 (talk) 23:40, 20 October 2013 (UTC)


A response by Eric Scerri.

I would like to briefly respond to the above points since they concern my work. First of all I am not the author of these Wiki pages on alternative periodic tables. Secondly, although I supported the Janet left-step table in my 2007 book on the periodic table, I have since then been more cautious. In my 2011 Very Short Introduction to the Periodic Table I propose another alternative version in which H is moved to the halogens while He is left at the top of group 18. I also suggest that on current knowledge there is not enough evidence to settle the question of the placement of H or He in the periodic table. Meanwhile it should be pointed out that there are several proponents for the left-step table who have published articles arguing in its favor. It is not just me. Among others are Henry Bent and Philip Stewart.

Thirdly, the fact that I am employed as a lecturer rather than a researcher in the chemistry department at UCLA has no bearing on the fact that I carry out research on the history & philosophy of chemistry and especially the periodic table. It is not the formal position that a scholar occupies but their research output that should be considered. I would ask the person commenting above to look closely at my research articles in the journals for history & philosophy of science and to consider retracting or modifying the above comment. This is the field in which I hold a PhD and in which I carried out postdoctoral work at Caltech and the London School of Economics (Department of Philosophy).

Fourthly, there have been some recent articles by Grandinetti that render the He in group 2 claim more plausible. Felice Grandinetti, Nature Chemistry, 5,438, (2013). There is also the work of Grochala from Poland who makes a direct case for the placement of He in the noble gases. W. Grochala, Polish Journal of Chemistry (in English), 83, 87-122, (2009)

To repeat, I am no longer trying to argue for the superiority of the Janet table, but just for greater discussion of the foundations of the periodic table. My own recent view is that He is too much like the other noble gases to be moved to group 2. But I am open to arguments that may be produced especially from quantum chemists. Several articles arguing the pros and cons of the Janet table have appeared in the Springer journal Foundations of Chemistry which I edit and which I invite the above commentator to consult.

Fifthly, I do not see the well-known anomalous configurations starting at Cr as being somehow more fatal to Janet's table than they are to any other alternative forms or indeed the traditional medium-long format.

Eric Scerri UCLA — Preceding unsigned comment added by 76.173.237.107 (talk) 03:48, 21 October 2013 (UTC)

I do not think that this article gives undue weight to the Janet table. It is mentioned as one alternative layout among several, eight with the names of their originators. The discussion of this table is four lines plus the figure, which makes the description much clearer. And the article does NOT claim that the Janet table is commonly used by physicists; it merely says it is near the physics end of the [chemistry-physics] continuum, meaning that Janet's reasoning is more physical than chemical. This says nothing about how many physicists actually use it today. Dirac66 (talk) 01:04, 22 October 2013 (UTC)
After rereading this carefully, I don't think the claims made in the original post by ip 216 stand scrutiny. I see no problem from the fact that Scerri (or whoever) is publicized on internet. I have worked with the periodic table pages here on en:wiki intesively, but I have not been impressed by some "internet presence" by anyone. I have enjoyed arguments, and I have used them to improve our wiki pages. If there is any right step forward, we could look at ADOMAH setup. Very interesting. -DePiep (talk) 19:04, 17 April 2014 (UTC)

Proposed merge with Placement of hydrogen in the periodic table

No evidence of notability of the "debate" mentioned in the Placement of hydrogen in the periodic table article. There is no content in the "Placement" page other than a restating of the title and a mention of four alternatives without any explanation of them. This "debate" would be better discussed in the existing Periodic table#Placement of hydrogen and helium section of the "Periodic Table" article. Ahecht (TALK
PAGE) 17:17, 19 April 2014 (UTC)

Confused. Well, this too should be just one subsection of the Open questions and controversies section. But that seems to be already the case, so here your proposed merger means leaving things as is. Or have I misunderstood something? Dirac66 (talk) 18:33, 20 April 2014 (UTC)
A little background: I made a WP:BOLD redirect of that page to this one. My redirect was reverted so I opened up this discussion (per WP:BRD). After I posted this proposal an administrator restored the redirect, hence the confusion. My proposal does reflect the current state as of the time of this post. --Ahecht (TALK
PAGE) 04:00, 22 April 2014 (UTC)
Support. Background is in Wikipedia_talk:ELEM#Stubs_of_brand_new_articles.21.. PAge was created in good faith to generate content. Creator admitted they could not provide that content (as self-stated). If such a page is useful, it could evolve from an existing section. -DePiep (talk) 20:03, 20 April 2014 (UTC)

The basic PT note

The basic 18-column PT note now says this; I added the [...] references:

This is an 18-column periodic table layout, which has come to be referred to as the common or standard form [a], on account of its popularity [b]. It is also sometimes referred to as the long form [c], in comparison to the short form [d] or Mendeleev-style [e], which omits groups 3–12 by placing their elements into the main groups. The wide periodic table[f] incorporates the lanthanides and the actinides, rather than separating them from the main body of the table. The extended periodic table adds the 8th and 9th periods, including the superactinides.[g]

Commenting:

In general, clearest is to count the element contaning columns (e.g., not the lefthand period number column).
[a]: useless words. Even in an 18-column form, there is no standard (in an 18-column PT, group 3 is not explicit). All the 18-column PT's do not have the same structure.
[b]: "popularity": a bad measure. Unsourced.
[c], [d]: "short, medium, long" meaning for the table changed in the PT history. The PT has changed from 8 to 18 to 32 columns, but the word "long PT" has not been redefined. Better to remove them (except from PT history sections, of course).
[e]: Mendeleev style: not good enough for us. btw, an external link?
[f]: "wide" is ambiguous, as said under [c]
[g]: Bad approach for the theoretical extensions.

All in all I think this note, in this primary place, should be changed. -DePiep (talk) 22:27, 27 April 2014 (UTC)

Can you then start the discussion of what specific changes should be made? I do think that we should indicate somewhere that almost all tables one sees these days in lecture rooms and textbooks follow essentially this format, with variations only in the elements listed as Group 3, and in the number and names of the newest elements listed. Dirac66 (talk) 23:29, 27 April 2014 (UTC)
I don't get your second sentence.
This is what I propose, somehow: rm "small, wide, long" mentioning. rm external link. Rephrase theoretical extension. So what about this:

This is an 18-column periodic table layout. Originally Mendeleev drew an 8-column table, with groups I–VIII. Later these groups were placed in this 18-column form, adding "A" and "B" group labels. Then, when the lanthanides and actinides were discovered as a unity (c. 1940), it was proposed to add these in separate rows below, as shown here. Formally these rows are incorporated into the main table, making a 32-column periodic table. Further theoretical elements are to be placed in extensions in periods 78 and higher.

-DePiep (talk) 23:45, 27 April 2014 (UTC) added links. -DePiep (talk) 23:48, 27 April 2014 (UTC) +more. -DePiep (talk) 23:53, 27 April 2014 (UTC)
I agree that this is an improvement, but I have two concerns.

(1) I would add the words widely used before 18-column. I agree we don't need to say common AND standard AND popularity, but one mention of wide use will help non-chemist readers who just want to know which form is the most used today. Yes, widely used is unsourced, but so is the rest of the paragraph. (2) In the last sentence, the elements in period 7 are no longer theoretical as they have now been discovered, admittedly in minute quantities. So I would modify your version slightly to:

This is a widely-used 18-column periodic table layout. Originally Mendeleev drew an 8-column table, with groups I–VIII. Later these groups were placed in this 18-column form, adding "A" and "B" group labels. Then, when the lanthanides and actinides were discovered as a unity (c. 1940), it was proposed to add these in separate rows below, as shown here. Formally these rows are incorporated into the main table, making a 32-column periodic table. The most recently discovered elements have been placed in extensions in period 7.

Dirac66 (talk) 02:43, 28 April 2014 (UTC)

point (1): Good point, text could be added. What about the detail that in the widely used 18-column PT, there are many variants wrt the group 3 (and the group2–3 gap) depiction and even definition?
point (2): you're right, period 7 is regular & complete. Now if I understand the topic correct, "extended PT" is a scientific term for periods 8 and higher. I changed my text (in this case, your last sentence about period 7 would need adjustment).
Adding point (3), wiki page layout only: couldn't we just put this whole footnote below the PT table, instead of above the legend? -DePiep (talk) 17:08, 28 April 2014 (UTC)
If the Mendeleev group I-VIII thing is not to detailed (& stays), we of course should mention something like "now group numbers 1–18". I think, for the reason of "too detailed", we can leave out stuff. And anyway, if you can agree with my earlier replies here our result is better than the current one. -DePiep (talk) 17:39, 28 April 2014 (UTC)

Proposed merge with Placement of lanthanides and actinides in the periodic table

No evidence of notability of the "Great Debate" mentioned in the Placement of lanthanides and actinides in the periodic table article. Much of the content of the "Placement" page is missing, and what little content there is would better serve to expand the existing Period 6 and 7 elements in group 3 section on this topic in the "Periodic Table" article. Ahecht (TALK
PAGE) 16:53, 19 April 2014 (UTC)

Support. The placement of lanthanides and actinides is no more notable than the other debates at Periodic table#Open questions and controversies. It should simply be included as one subsection of that section. I would place it immediately after the Period 6 and 7 elements subsection. Dirac66 (talk) 18:30, 20 April 2014 (UTC)
Support. Creator discussed this at Wikipedia_talk:ELEM#Stubs_of_brand_new_articles.21. I strongly got the impression that the creator started the page to stimulate content development (description of the Great Debate?). I have expressed my opinion that any separate page should evolve out of a section (by growing & proving and a fork out). Ahecht states the same here, independently. -DePiep (talk) 18:47, 20 April 2014 (UTC)
  checkY Merger complete. --Ahecht (TALK
PAGE) 14:07, 13 May 2014 (UTC)
To clarify what was done, this merger was carried out in two steps: First on April 16 the content of the old article Placement of lanthanides and actinides in the periodic table was added to this Periodic Table article, while temporarily retaining Placement of lanthanides ... as a separate article. Then after the above discussion, the article Placement of lanthanides ... was replaced as a redirect on May 12 (yesterday). That is why yesterday's edit did not lengthen the article, although labelled as a merger in the edit summary; the lengthening occurred on April 16. Dirac66 (talk) 01:03, 14 May 2014 (UTC)

The first picture in the "History" section

Why isn't fluorine coloured as having been known in 1869? It was certainly known (Mendeleev put it in his 1869 table); it just hadn't been isolated (which Moissan did in 1886: this seems to be the date the article is using). This looks very odd, especially as the pictures of Newlands' and Mendeleev's periodic tables given below have F. Double sharp (talk) 09:14, 15 May 2014 (UTC)

 Done Changed the image, now F = known in 1869. -DePiep (talk) 11:32, 15 May 2014 (UTC)
Thank you! Double sharp (talk) 11:53, 15 May 2014 (UTC)
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