Talk:Periodic table

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)

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)

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)

"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.