Talk:Periodic table/Archive 5

Abolition of GNU/FDL??
Why has this template been made so incredibily complicated, with tons of transclusions, whistles, bells etc. Is this done on purpose to make sure that no teacher in the world can copy it and adapt it for his/her class. Isn't that the opposite of what GNU/FDL is supposed to do?

Jcwf (talk) 16:40, 8 January 2009 (UTC)


 * I do kinda agree with you that you have to understand a lot of technical crapola about tables and templates and transclusions in order to mess around with the Wikipedia periodic table for a class, but I think that every little addition of a doodad was done for a good technical reason that made sense to a consensus of reasonable people. The fact is that it's not easy to create a rational system of interconnecting doodads to put a lot of visual information onto the web in a small space. If you just want to copy the table, use a screen capture. It's just not a goal of Wikipedia to create a digital environment where teachers can easily create an alternate universe for students where the noble gases are to the left of the pnictogens. But with a little effort you still should be able to figure out how to do that anyway. If you want to tweak simple things around for a class then I think you only need to know the information in Help:Table and then you can copy the content in Periodic_table_(text_only) to a sandbox and mess around with it there. After you do that for a while, I think you'll start to appreciate why Template:element cell was used in Periodic_table_(standard). Flying Jazz (talk) 06:02, 18 January 2009 (UTC)

chemistry and all its defindings
chemistry has long been known as a branch of science that study matters and the changes it undergoes but do we really understand the basic logic in this defination? as we all may know matter is anything that has mass and take up space so what type of matter is out there? eg: eggs is a common repilca of a matter it has mass and is also take up space so now you might be wondering what are the type of change does matter goes through well we have a physical change and a chemical change example of both are burning paper and melting of ice, tearing paper or rust on an old car. thanks for your time MD.Abbaccus S Dokie, university of Liberia —Preceding unsigned comment added by 76.117.226.174 (talk) 01:39, 23 January 2009 (UTC)

Groups And Periods (Pnictogens)
Some other groups in the periodic table display fewer similarities and/or vertical trends (for example Groups 14 and 15).

Isn't group 15 called the Pnictogens. —Preceding unsigned comment added by 86.171.40.3 (talk) 11:04, 25 January 2009 (UTC)
 * yes --BlueEarth (talk | contribs) 19:08, 25 January 2009 (UTC)

The graph in the section on periodicity shows ionisation energies down a group (the noble gases), not across a period as it wrongly claims. The caption clearly does not make sense with the graph. If someone has a correct graph it ought to be replaced.
 * It shows both periodicities, down the groups and periods. I can read the graph fine. What are the problems? Materialscientist (talk) 22:05, 13 June 2010 (UTC)

Sorry my mistake. Should i remove my earlier comments to save space on the discussion page? —Preceding unsigned comment added by 86.144.101.33 (talk) 18:53, 15 June 2010 (UTC)
 * Um, no. Lanthanum-138 (talk) 06:11, 8 May 2011 (UTC)

IUPAC recommended nomenclature
According to IUPAC, the inner-transition elements should be called Lanthanoids and Actinoids instead of Lanthanides and Actinides. (So is trans-actinoids.) Zhieaanm (talk) 00:44, 5 February 2009 (UTC)


 * I have never heard these "-oids" terms before. Where, exactly, can they be found?  Could you provide a url?  RobertAustin (talk) 16:39, 21 July 2009 (UTC)

See http://old.iupac.org/reports/periodic_table/index.html and http://old.iupac.org/reports/periodic_table/IUPAC_Periodic_Table-22Jun07b.pdf.

Ben (talk) 17:10, 21 July 2009 (UTC)

New layout?
Shpackov A.A.Dear Collegues! Alas! You had made methodologic mistake in Your publication. H has not neutrone and therefore H could not to have isotopes as isotopes are chemical elements having (!!!) the same number of protones and electrounes and different quantity of neutrones. D is chemical elements like all isotopes do. Mendellev`s periodic law and table are archaic, and new chemical elements properties law and new (homological) classification had were created /1. Shpackov A.A. The nature and boundaries of information science(s). / J. Amer. Soc. Inform. Sci., vol.43, no.10, p.678-681, and the Universal Classification scheme, 1992 - see ATOM class; Шпаков А.А. Новый закон и классификация химических элементов, изотопов и ионов. / 2. Бюллетень Московского общества испытателей природы. Отдел геологический. Москва: Изд-во МГУ, т.68, №1, с.136-137, 1993; 3. Шпаков А.А. Карта Знаний. Москва: Информот, плакат формата А 2 со схемой на одной стороне и текстом на обратной, 2005/. The chemical elements properties are depending from all elementary particles, having form chemical elements and from particles proprties and its relationships in atoms, and chemical elements proprties functions are linear in the chemical elements homological rows /2/. —Preceding unsigned comment added by Shpackov (talk • contribs) 08:12, 20 February 2009 (UTC)
 * In the periodic table, "H" is the element "hydrogen", not specifically "the 1H isotope of hydrogen", just like all other element symbols refer to all isotopes of their element. Deuterium is special enough that it is assigned its own symbol, and when one is talking about isotopes of hydrogen, "H is 1H and D is 2H". DMacks (talk) 08:21, 20 February 2009 (UTC)
 * WP:OR, in any case. Lanthanum-138 (talk) 09:10, 15 March 2011 (UTC)

Atomic Weights?
I was looking at the Periodic Table...

Trying to figure out molar weights... but unfortunately there were no Atomic Weights in the Periodic Table. Obviously it is a complicated subject for an introduction, but very useful for determining quantities of reagents, for example acid/base equivalents.

See: http://www.webelements.com/nexus/Printable_Periodic_Table --Keelec (talk) 09:40, 28 February 2009 (UTC)


 * Periodic table (large version) includes atomic mass data. Vsmith (talk) 13:28, 28 February 2009 (UTC)


 * The same number which is most correctly called the "average atomic mass" (but often called, incorrectly and confusingly, the "atomic weight") is the mass of the average atom (which doesn't actually exist; it is a weighted average of masses for the isotopes of the element in question which appear in nature) for a particular element, IF the unit following the number is "u," the symbol for the atomic mass unit. If the unit is changed to "g" (for "grams"), but the number is left exactly the same, THEN you have the molar mass.  The molar mass is, of course, much larger than the average atomic mass, even though the numbers match -- for a gram is far larger than an atomic mass unit, and you are giving the mass of ~6.022x10^23 atoms, rather than just one. RobertAustin (talk) 16:37, 21 July 2009 (UTC)

The Father of the Periodic Table
"Dmitri Mendeleev, father of the periodic table" is not a correct caption, because it needs to be:

"Dmitri Mendeleev, the father of the periodic table".

Likewise, George Washington is the father of our country;

Edward Teller was the father of the hydrogen bomb;

Marx was the father of Communism;

John Adams was the father of John Quincy Adams;

Darth Vader is the father of Luke Skywalker;

Sir William Henry Bragg was the father of Sir William Lawrence Bragg;

And so forth. Dale101usa (talk) 18:26, 1 March 2009 (UTC)


 * All of your other examples are different: you're writing a complete sentence ("is"/"was"), so you require some article and have to choose definite "the" rather than indefinite "a". It's a small clause (I think that's the term). See for an analogous example illustrating the non-need for an article. That said, adding "the" would make it seem more like it's his title, which is the whole point of that caption, rather than just as a description/adjective/synonym of the person. DMacks (talk) 21:04, 1 March 2009 (UTC)


 * There is nothing wrong, grammatically, with having "Dmitri Mendeleev, father of the periodic table" appear as part of a sentence. It is also fine to include the article "the" in this same phrase.  This is simply a case where essentially the same thing can be written, correctly, in at least two different ways -- nothing more than that.  It's also hardly worth an argument. RobertAustin (talk) 16:27, 21 July 2009 (UTC)

Karl Marx, father of Communism... —Preceding unsigned comment added by 156.34.163.171 (talk) 02:13, 28 July 2009 (UTC)
 * You think the word the has to be in there? (The) can be in there, but...           it doesn't have to be.  —Preceding unsigned comment added by Wd930 (talk • contribs) 02:01, 4 December 2010 (UTC)

(The)         only has to be in there if it's                         ("Dimitri Mendeleyv                is                                                                                the father of the periodic table".)

Oh, you could say that Dimitri Mendeleyv is father of the periodic table.Wd930PeriodicTable (Talk) (talk) 02:21, 15 December 2010 (UTC)


 * BUT this is all missing the point! If anyone was the father of the periodic table, JAR Newlands was, in 1865. He produced the first table with periods (octaves) and proposed the existence of previously undetected elements such as germanium. By this reckoning, Mendeleev was a foster parent or kidnapper, for his contribution was to rediscover Newlands work and reprint it in c.1869 using an inverted format, for which he got recognition and a medal from the Society of Chemists. Embarrassed by their earlier short sightedness, the SoC did not recognise Newlands until 1887, although by then the damage had been done and Mendeleev was popularly, if incorrectly, credited. Ephebi (talk) 12:13, 17 June 2011 (UTC)


 * Relax, Newlands wasn't. He made many mistakes (putting together B/Al/Ti/Zn, or C/Si/Cr/In), and tried to expanded his octaves, true at that point for the lighter elements, to all elements. And why did he try to fix music and chemistry? That's not serious... Even through Mendeleev may be influenced by this English dude, and Newlands was the one to think first of periodicity, he wasn't the father of the table we know. I know that Mendeleev wrote something like (who knows when?), "In his law I can see the start for the search of the periodic law"--R8R Gtrs (talk) 12:50, 17 June 2011 (UTC)


 * As you appear unaware of 'the dude's efforts, this extract from the ODNB may answer your question: "Newlands earned a place in chemical history by his partial anticipation of D. I. Mendeleyev's periodic law... Newlands noticed that elements with similar properties occurred at regular intervals. In 1864 he asserted that ‘the eighth element starting from a given one is a kind of repetition of the first, like the eighth note of an octave in music’ (Chemical News, 20 Aug 1864, 94), and in 1865 he formalized this relationship as the ‘law of octaves’. His proposal met with opposition and even ridicule" (Very little changes, it appears!) In his letter published in Chemical News 25 Aug 1865 Newlands clearly differentiates between Ti & Zn, so I don't know what your source claiming his mistakes is using. The only mistake that I am aware of is his identification of "Di" (didymium, later separated into praseodymium (Pr) and neodymium (Nd)). There was a discussion of the two gentlemen's contribution in Chemistry Review in 2003, where Newlands was described as the "almost originator", and the first person to use atomic numbers. That is not to diminish the Russian dude's contribution, but to put it into an accurate context of an incremental advance. Ephebi (talk) 14:47, 17 June 2011 (UTC)


 * OK, I don't mean Newlands was unimportant :) He has certainly found its place in periodic table history, but he wasn't its father. Even when you cite ODNB, it says the law is Mendeleev's. I might've mistaken, I won't argue. Just note that Mendeleev created another table, which got famous later (his predictions on properties of Sc, Ga and Ge played their role), which may be influenced by Newlands' one. Are we OK with it now?--R8R Gtrs (talk) 15:28, 17 June 2011 (UTC)


 * Ephebi Are you certain about "Chemical News, 20 Aug 1864, 94"? I spent all morning here http://web.lemoyne.edu/~giunta/EA/NEWLANDSann.HTML and noticed this 'J. A. R. Newlands, "On the Law of Octaves," Chemical News, 12, 83 (1865a) and J. A. R. Newlands, "On the Cause of Numerical Relations among the Equivalents," Chemical News, 12, 94 (1865b). I still can't find any citation confirming that this Chemical Society actually acknowledged Newlands achievements. Granted, he wasn't as singularly mapped to the creation of the Periodic table of the elements as Mendeleev, but he seems to be deserving of SOME sort of recognition from those difficult individuals at that Chemical Society from what I could tell from reading through those secondarily sourced transcripts! --FeralOink (talk) 23:09, 23 February 2012 (UTC)


 * note that Mendeleev's Periodic law is different from Periodic table.  A 'periodic' table originated from Newlands in 1865, but in a somewhat different format. Mendeleev developed the table into the modern form that we know & love.  At the risk of sounding pedantic (which I hate!), whether I'm OK with it is neither here nor there  8^} ... The question is, is it represented accurately on the page?
 * To be encyclopaedic, we need to be precise on these terms. IMHO the page is currently slightly inaccurate or misleading on a couple of paragraphs which need rewording;
 * "... its invention is generally credited to Russian chemist Dmitri Mendeleev, who developed a version of the now-familiar tabular presentation" - the table came first from Newlands, which Mendeleev modified it. The "generally credited" statement is based on the Chemical Society's publications, which they corrected 130 years ago. Perhaps change to "often credited" and add "after an earlier version by JAR Newlands"
 * "One of the strengths of Mendeleev's original presentation was the prediction of the properties of then-undiscovered elements expected to fill noticeable gaps" - Newlands' Law of octaves had already achieved this. Re-word to say the "Newlands-Medeleev tables"
 * WP is not a forum for revisionism, but in this instance the Chemistry Society took 20 years to revise its credits. It seems its taking 130 years for WP to catch up ;-) Ephebi (talk) 16:56, 17 June 2011 (UTC)


 * Against. I won't even argue. Keep in mind WP:V — if even Newlands did more than Mendeleev, the table is still cited as Mendeleev's, not as Newlands—Mendeleev's or any other way. An argue about nothing...--R8R Gtrs (talk) 17:03, 17 June 2011 (UTC)

Atomic Mass vs. Atomic Weight
I believe you are referring to atomic weight in the Arrangement paragraph.

In printed tables, each element is usually listed with its element symbol and atomic number; many versions of the table also list the element's atomic mass and other information, such as its abbreviated electron configuration, electronegativity and most common valence numbers.

Atomic mass refers to a single atom of one isotope and would have integer values while atomic weights, which are seen on the PT below the element identity, tend to have non-integer values because they are the weighted average of all the naturally occurring isotopes.

--Libertas81 (talk) 04:38, 20 March 2009 (UTC)


 * I do believe the thing Libertas81 is referring to, which has values which are integers, is more properly (and less confusingly) called the "mass number," and is simply the number of nucleons in the nucleus for any particular nuclide. I have seen "atomic mass" values given many, many times as long decimals.  In my copy of the CRC Handbook of Chemistry and Physics (old, admittedly; '96-'97), the CRC tries to please both sides in the long "table of the isotopes" section by labeling a column (with long-decimal values below) as "atomic mass or weight."  I would be quite curious to know how this column is labeled in the newest edition of the Handbook -- does anyone have a copy handy (no pun intended)? RobertAustin (talk) 16:21, 21 July 2009 (UTC)

This "atomic weight" thing chemists do (all the time) drives many physicists crazy, but it's not going to change any time soon. "Mass" is clearly the appropriate word to use, for it is the amount of matter in an atom that is being described, not the pull of gravity on that atom. Chemists should know better; perhaps they are sticking with the incorrect term merely to try to annoy the physicists. The historical rivalry between people in these two fields is an interesting one, perhaps even one worthy of a Wikipedia article itself. RobertAustin (talk) 16:10, 21 July 2009 (UTC)

Helium not primordial?
What definition makes Uranium "primordial" but Helium "from decay"? If Helium isn't primordial then everything except Hydrogen is created "from decay". Also, why is Plutonium "synthetic" rather than "from decay" as Plutonium states that it can be found in nature. OrangeDog (talk • edits) 01:52, 16 April 2009 (UTC)


 * It depends on what you mean by primordial. Nearly all helium on Earth comes from decay. Helium in the universe mostly comes from the Big Bang, and secondly from stellar fusion. --Itub (talk) 13:03, 16 April 2009 (UTC)


 * That's my question. What definition of primordial makes the table as shown consistent? And why not have the usual radioactivity information instead? OrangeDog (talk • edits) 13:54, 16 April 2009 (UTC)

. I agree that pu should be labeled from decay pu-244 is found in trace amounts. --Weetoddid (talk) 06:32, 27 May 2009 (UTC)

It is clearly ridiculous to have Pu labeled "primordial," and He not labeled with the same word. A major problem here, though, is that EVERY version of the periodic table I have ever seen shows Pu as a "synthetic" element, even though we have known for years that it does occur in nature, in trace amounts. The reasons for this are historical -- Pu was first detected after being synthesized in a nuclear reaction, and the fact that it does occur in nature was discovered much, much later. It seems that this problem of inconsistency exists throughout the field of chemistry -- it's not just a Wikipedia problem at all. RobertAustin (talk) 16:05, 21 July 2009 (UTC)
 * Why does it say that plutonium is a primmordial? I'm pretty sure that's wrong. This is not an edit request. --**Najezeko**:) 06:08, 15 January 2011 (UTC)

Didactics: shell filling
re: "As another example, both carbon and lead have four electrons in their outer shell orbitals."

Editorial comments: 1. As another example of what? Give the concept a name or phrase, and repeat the name or phrase here. 2. So what? Derive the logical consequences. "Therefore, ..... " Say what you would expect to find, observe. 3. Compare and contrast: my goodness, 4 electrons and one is the basis of carbon chemistry, the whole industrial world of organic chemistry, and the other falls with a thud like lead. The reader is left curious as can be, but without answers. People smarter than I might add, "Despite the similarities/principles illustrated in (2), the two elements behave so differently chemically speaking because . . . "  Look, my Ph.D. is in psychology but, gentlemen and ladies, there has to be a teachable point about chemical bond formation hidden here. Have fun! Reveal it! Thank you for all achieved so far, --jerry Jerry-va (talk) 12:35, 31 May 2009 (UTC)

Re-write
This article assumes too much of the readers scientific knowledge and should be written where terms are better explained. I doubt it is of much use to a 13 year old and a 13-18 year old is most likely user to read this article. —Preceding unsigned comment added by Jacobsdad (talk • contribs) 01:35, 14 June 2009 (UTC)


 * I respectfully disagree. Wikipedia articles should, in my opinion, be written for an intelligent and educated adult audience, NOT for the average 13-year-old.  It is not hard at all, with a Google search, to find more kid-friendly sites to explain the periodic table to younger folks, in an age-appropriate manner. RobertAustin (talk) 15:57, 21 July 2009 (UTC)
 * We should write for everyone. Not shy away from technical/advanaced material and not dumb it down, but also try to include some accessible basics for topics that non-advanced readers might want. The Periodic Table really is an important concept that even non-advanced students will encounter in school, and it really does have a lot of easily accessible information related to it. OTOH, we also have a whole "Wikipedia Simple", which has a Periodic table article, that is specifically targeted towards less advanced readers. A shame IMO that so few readers know about Simple: any page that has a companion there is accessible via a link in the "languages" sidebar. DMacks (talk) 16:16, 21 July 2009 (UTC)
 * I can see why we're losing ground in any progress towards getting the inquiring readers to consider the merits of the Janet periodic Table. The article mentions it in the text, but doesn't refer to it in the See Also section, where most people go to get additional information. And when you start talking about atomic numbers 119 and 120, the difference in the formats of the two tables becomes significant.WFPM (talk) 19:28, 28 July 2009 (UTC)Note that the Basic English periodic table  article makes even less mention as to alternative periodic tables.

And I notice that even this more sophisticated presentation of the table there is no rationale given for the relative lengths of the successive periods, which involve the numerical sequence 2, 8, 8, 18, 18, 32, and 32 in the standard table versus the sequence 2, 2, 8, 8, 18, 18, 32, and 32, in the alternate Janet table. This might be of assistance to people trying to understand the relative merits of these tables.WFPM (talk) 18:29, 25 April 2010 (UTC)

Copernicum?
Wasn't this announced by IUPAC recently? —Preceding unsigned comment added by 150.101.68.60 (talk) 07:10, 21 July 2009 (UTC)
 * Not as the official name yet. I'm sure IUPAC will announce it on their website. DMacks (talk) 07:29, 21 July 2009 (UTC)


 * Here are some relevant links -- http://www.popsci.com/scitech/article/2009-07/element-112-named-copernicum and http://www.newser.com/story/64554/after-13-years-new-element-gets-name-copernicum.html -- apparently, this name is now in the popular press for element 112, now called "ununbium," but the IUPAC has a six-month waiting period for discussion, now begun, before the name becomes becomes official. My recommendation is that "copernicum" be mentioned only on talk pages, and not in actual articles, until after the IUPAC has made their official ruling.  It won't be THAT long.  Also, if you look at the two articles I provided links for, you'll note that there is a bit of confusion of the exact spelling of the new name, AND no mention of its symbol, either.  My money is on "Cp," but that is nothing more than a personal guess.  Not article-worthy information just yet, but definitely something to keep an eye on.  RobertAustin (talk) 15:53, 21 July 2009 (UTC)
 * Yup, there was already discussion and consensus among the WP chemistry not to jump ahead of official IUPAC naming in the articles related to this element. DMacks (talk) 16:09, 21 July 2009 (UTC)

Need to edit your article better
Under the Periods section someone has mischieviously entered the text "watchin porn is hawt ". Possibly true but a bit off-topic. Nucdesigner1 (talk) 02:32, 18 September 2009 (UTC)Nucdesigner1


 * Yes, that happened less than half an hour before you read it, and it was taken out shortly thereafter. We get anonymous vandals like that all the time, and if it starts happening too frequently the article can be semi-protected against such. --Glenn L (talk) 06:48, 18 September 2009 (UTC)

Invalid statement
"The elements ununbium, ununtrium, ununquadium, etc. are elements that have been discovered, but so far have not received a trivial name yet."

This statement is wrong. As the entry on "trivial names" explains,  a trivial name is a commonly used name for something which has an alternative "correct" name. For example, "tiger" is a common or trivial name for "panthera tigris". Or "tartaric acid" is a common or trivial name for what a scientist should properly call 2,3-dihydroxysuccinic acid as a "correct" name.

The proper names of the chemical elements ( hydrogen, helium, plutonium etc etc )  are their proper and correct names. They are not common or trivial nicknames.Eregli bob (talk) 03:39, 4 October 2009 (UTC)

This statement can be updated. As the entry on "ununbium" explains,   the element "ununbium" has a name of copernicium.

Liquid Color
I apologize if this seems not that important, but using the color green for liquids makes it really hard to see which elements are liquids - I can barely see that Mercury is a liquid. Can another color be chosen? Can you use a bolder font for the numbers so they stand out?--66.60.79.20 (talk) 17:14, 9 October 2009 (UTC)


 * I second the motion; I was just about to suggest bold numbering myself. -- Jeffryfisher (talk) 23:49, 2 December 2010 (UTC)

System and representation
This article is mostly about the Periodic System - an abstract pattern of relationships between chemical elements, of which tables (arranged in rows and columns) are one form of representation, parallel with other forms of representation such as spirals or concentric circles. This was generally understood by Jan van Spronsen and Edward Mazurs who published reviews to celebrate the centenary of Mendeleev's table: The Periodic System of chemical elements: the first hundred years and Graphic representations of the Periodic System during one hundred years respectively. Chemists seem to have forgotten this distinction and now write as if tables - or the Table - were the only representation. In fact spirals are more faithful to the nature of the system, since the sequence of elements is continuous and must be chopped into sections to fit into a table. So can we please have an article about the System, with pointers to separate articles about tables (in the plural), spirals etcetera? (Pjstewart (talk) 11:10, 30 October 2009 (UTC))


 * The standard Periodic Table is obviously the transient result of an effort by interested parties to create a "method out of madness" organization of informational material about matter. It was created by a Chemist, and is currently controlled by IUPAC, and accordingly is not much concerned with the physical processes whereby the matter was created and accumulated in the first place. And it is hoped that as more is learned about the physical properties of of the basic particles of matter, the table can be modified to accommodate the organized inclusion of that information into the organization of the table.

Radioactivity
Under the "Structure of the Periodic Table" section, the article says that all elements after 83 (bismuth), starting with 84 (polonium) are radioactive. Isn't bismuth technically radioactive? Also, a bit below that, it says that plutonium is found as a radioactive decay product, while it is actually found in trace quantities in nature. —Preceding unsigned comment added by 173.15.210.42 (talk) 19:36, 4 December 2009 (UTC)
 * Yes, but bismuth is not considered "radioactive" in practice. As to plutonium, "found in nature" and "as a product of radioactive decay processes" are not contradictory because radioactive decay processes occur in nature and do not imply "synthetic". Materialscientist (talk) 00:38, 5 December 2009 (UTC)
 * Regarding plutonium, I think the point was that at least some of the plutonium found in nature can be considered primordial and not the product of decay. --Itub (talk) 18:19, 7 December 2009 (UTC)
 * That was my point with plutonium; it is found in trace primordial quantities. Elium2 (talk) 20:44, 7 December 2009 (UTC)
 * ...and now I'm here precisely because I am surprised to see Pu labeled primordial when it isn't. With its longest half-life being 24,000 years, there have been 160,000 half-lives in Earth's 4 billion years. Quick, what's the inverse of 2^160000? I think it's greater than the number of atoms in the universe, so Pu is not primordial. Pu is at best a natural decay/reaction product. Am I allowed to edit it myself, or should I leave that to the next person who agrees? -- Jeffryfisher (talk) 23:28, 2 December 2010 (UTC)
 * Incidentally, when I started this section, I did not have a user account! Also, I did not notice that there was a very similar section above. Elium2 (talk) 19:53, 18 December 2009 (UTC)
 * re Bismuth: It's unstable, but with a half life many times the age of the universe, its radioactivity is virtually undetectable (and proven only relatively recently, as described in the Bismuth article). See Bismuth  -- Jeffryfisher (talk) 23:28, 2 December 2010 (UTC)
 * I disagree with your plutonium claim. Plutonium-244 is the most stable isotope of plutonium, with a half-life of about 80 million years (~1/55 Earth's age). And 2^55 is much smaller than the Avogadro constant, so of each 244 g of Pu-244 originally on Earth, thousands of atoms still exist today.--Roentgenium111 (talk) 22:45, 5 December 2010 (UTC)

Dice games involving the Periodic Table?
Does anybody know of any dice games involving the periodic table, and moving pieces around, and buying, securing, or contesting elements as in Monopoly?

The main article would be improved if there were a paragraph or two on games involving the periodic table. Dexter Nextnumber (talk) 05:34, 19 December 2009 (UTC)


 * This isn't the place for that. Look on the internet, there are many other pages that can help you out. —Preceding unsigned comment added by 90.210.60.185 (talk) 18:17, 5 February 2010 (UTC)


 * A more interesting idea for you to try is to get some models of atomic nuclides that are magnetized and then put them together so they make a composite structure that you think might resemble the structure of the nucleus of the atomic nuclei of the elements of the periodic table. You might be surprised at what kind of structure that you come up with. You might look at the models at Talk:Nuclear model for one set of examples.WFPM (talk) 02:29, 19 March 2010 (UTC)


 * If you find such games, then start a separate Wiki article for them. Then maybe you could convince folks to put a further reading link on this or a disambiguation page -- Jeffryfisher (talk) 23:34, 2 December 2010 (UTC)

lanthanoid(s) and actinoid(s) vs. lanthanide(s) and actinide(s)
Please see this this community discussion on whether or not we should be using the IUPAC nomenclature (lanthanoid or actinoid) vs. common usage (lanthanide or actinide). Polyamorph (talk) 08:41, 10 February 2010 (UTC)


 * I don't see much (any) discussion at that link, and the -ide vs -oid choices seem pretty random at the moment. &mdash; JLundell  talk   17:50, 7 July 2010 (UTC)
 * Random where? Materialscientist (talk) 22:15, 7 July 2010 (UTC)

Color Blindness
If anyone cares, the table is kind of difficult for people with color blindness to read. The "transition metals" and "other metals" are hard to distinguish and "other nonmetals" and "halogens" are hard to distinguish. —Preceding unsigned comment added by 96.243.184.248 (talk) 03:04, 21 February 2010 (UTC)


 * Sadly, no one cares. This table has been in use for a number of decades, so it's a little late to worry about that.
 * Why don't you find a color-blind chemist or physicist and ask how he/she/it deals with it? —Preceding unsigned comment added by 69.171.176.158 (talk) 14:49, 22 July 2010 (UTC)

Also, I think for people who are color blind, they might not be able to distinguish between liquids, and gases. 71.217.65.69 (talk) 21:34, 3 March 2011 (UTC)

Mnemonic
How about adding a few? They can be helpful for people.Mango bush (talk) 19:04, 31 March 2010 (UTC)

I can't help you with a Mnemonic. But might notice that as the numbers of elements in the periods expand, they expand in accordance with a pattern. For instance in the Janet table, the period expansion sequence pattern is 2, 2, 8, 8, 18, 18, 32, 32, and that can be better understood by expanding it to 2, 2, ((2+4)+2), ((2+4)+2), ((2+4+4)+(2+4)+2), ((2+4+4)+(2+4)+2), ((2+4+4+4)+(2+4+4)+(2+4)+2), and ((2+4+4+4)+(2+4+4)+(2+4)+2),. Then after you learn the names of the elements, you can then associate them in each series by starting with the first 2 and then associating the remainder in sequences of 2 plus the appropriate additional number of groups of 4, and then a last 2, which your mind pretty quickly learns to associate.WFPM (talk) 19:02, 25 April 2010 (UTC) If you try it with just the atomic numbers, you'll find that it's easy to understand and memorize the pattern, and the hard part is associating the names with the numbers.WFPM (talk) 19:38, 26 April 2010 (UTC)

If you want to understand how this accumulation process can work for real entities you can use children's blocks to make a model of the accumulation process. Remember that each addition is of 2 blocks. So the first group consists of 4 blocks together in a square. Then the second group consists in a second 4 block square on top of the first group. The the third group consists of a wraparound group of 4 + 8 = 12 blocks around the junction between the top and bottom first and second group blocks, and then the third group ends with an additional 4 blocks on the top. This is repeated in the fourth group. Then the fifth group consists in a 20 block wraparound of the third and fourth groups plus an additional 12 block wraparound plus an additional 4 blocks on top. This is repeated in the sixth group, which gets you up to an accumulation of 56 pairs of 2 blocks. The seventh and eighth groups involve the same accumulation process with each group accumulating 64 blocks (32 pairs), and winding up with a structure with an accumulation of 240 blocks (120 pairs) The structure is essentially an 4 sided octahedral structure.WFPM (talk) 18:57, 24 March 2012 (UTC)

And if you use cylindrical (Neodymium) magnets to make these models, you'll find out that their magnetic properties are consistent with the structure of the model and help hold the structure together. Approximately 1 centimeter diameter units are a good size and thus show an approximately 10E^13 amplification factor. I used 3/8 th's inch diameter.WFPM (talk) 21:26, 25 March 2012 (UTC)

Table
It says Element 117 hasn't been discovered yet when in reality it has just been. —Preceding unsigned comment added by 85.97.41.86 (talk) 21:12, 21 May 2010 (UTC)
 * There was a switch to a version dating back to February. This was done after a discussion about the actinides and lantanides place in the PSE and the IUPAC PSE. It took some time and therefore the february version did not contain element 117 info.--Stone (talk) 22:54, 21 May 2010 (UTC)


 * This is a chronic problem with Wikipedia authors and editors: they aspergersly refuse to use phrases such as "as of such and such a date..." which leads, for example, to hard-coding things such as celebrities' ages, number of known elements, etc.


 * BTW, what does Porn Star Experience have to do with chemistry and physics? —Preceding unsigned comment added by 69.171.176.158 (talk) 14:56, 22 July 2010 (UTC)

Edit request from 98.26.57.143, 4 June 2010
below the table, in the key it states that the states of the elements are at standard temperature and pressure, as they should be but goes on to say that standard is 0 C and 1ATM. it should say 25 C, or room temperature. 98.26.57.143 (talk) 23:40, 4 June 2010 (UTC)
 * There are two definitions of standard conditions for temperature and pressure, 0°C and 20°C. This is just a convention and it does not affect the table because no element changes its state between 0 and 20°C. (Even if it did, my eye can't really distinguish the supposed change in the color of atomic number :) Materialscientist (talk) 23:54, 4 June 2010 (UTC)


 * Not strictly true. You are confusing boiling point and evaporation.  Bromine, for example, easily evaporates at room temperature at sea level.  Leave a beaker of bromine sitting around and eventually it will all be gone.  Change of state.  Doesn't affect your basic point though.  —Preceding unsigned comment added by 69.171.176.158 (talk) 15:15, 22 July 2010 (UTC)

Naturally Occurring.
Human beings are naturally occurring and so are their products, we say honey is naturally occurring, why are we any more special than bees.

By stating that several elements are not naturally occurring, you infer that Human endeavours are supernatural, they are not, this article needs editing. —Preceding unsigned comment added by 86.11.153.79 (talk) 16:52, 4 October 2010 (UTC)

Hydrogen
Hydrogen has been classified as an alkaline earth metal. Here you have it as other non-metals. —Preceding unsigned comment added by 98.110.80.51 (talk) 22:03, 10 November 2010 (UTC)
 * Our Alkali metal article notes in its intro "Hydrogen, although nominally also a member of Group 1, very rarely exhibits behavior comparable to the alkali metals" (that makes sense...not metallic at normal conditions, etc.). I can't think why it would be considered an alkaline earth metal (Group 2) at all--got a good reference to support this idea? The IUPAC Red Book (page 51) states "The following collective names for like elements are IUPAC-approved: alkali metals (Li, Na, K, Rb, Cs, Fr), alkaline earth metals (Be, Mg, Ca, Sr, Ba, Ra)" and does not include H in any specifically-named group. DMacks (talk) 22:13, 10 November 2010 (UTC)

What about alkali earth metals vs. alkaline earth metals? —Preceding unsigned comment added by Wd930 (talk • contribs) 00:52, 2 December 2010 (UTC)


 * As DMacks pointed out, we're following the convention of IUPAC-approved element category names in the Red Book. IUPAC follows names in common usage, and these names are often unusual for obscure historical reasons. Look at this: Yazoo City was named after the Yazoo River which was named after the Yazoo tribe, so Yazoo means...well...nobody knows. Compared to that level of confusion, the difference between alkali and alkaline is pretty minor! Flying Jazz (talk) 09:27, 2 December 2010 (UTC)

Edit request from 122.164.119.137, 12 January 2011
The Periodic Table Picture is outdated... Element 119 has been discovered! Pls update image.

122.164.119.137 (talk) 16:21, 12 January 2011 (UTC)

Wow! I will edit it and add it!!!! IF I get a credible source for the claim. --Stone (talk) 16:31, 12 January 2011 (UTC)
 * Red information icon with gradient background.svg Not done: please provide reliable sources that support the change you want to be made. → ♠ Gƒoley ↔ Four ♣ ← 16:52, 12 January 2011 (UTC)

Alternative versions
The first line of the Alternative Versions Subject Heading could be modified to read Other alternative periodic tables exist, including a Dynamic Interactive Table. —Preceding unsigned comment added by 75.79.21.53 (talk) 18:36, 21 January 2011 (UTC)
 * No, we don't need to link a non-notable non-example of them in an inappropriate location. DMacks (talk) 20:22, 21 January 2011 (UTC)

Phosphorus, not Phosphorous
In the first section, showing the Table itself, the name of Element 15 should be "Phosphorus", in title and link, to match the page to which it links. "Phosphorous" is an adjective. Consult a reputable dictionary, such as Chambers' or the Concise Oxford, or even Webster. 94.30.84.71 (talk) 14:13, 15 February 2011 (UTC)
 * In the table in the section titled "Structure", phosphorus appears correctly. In fact, I cannot find use of the term "phosphorous" anywhere in the article.  Can you please be more specific about where you think there is a problem?   ChemNerd (talk) 14:21, 15 February 2011 (UTC)

Americium is also found in nature
I am aware that most sources state that the number of elements found in nature is 94 (those with atomic numbers 1-94). However, several other sources raise that number to 95, and include americium (atomic number 95) to those elements found in nature. I hold a copy of "HUTCHINSON GALLUP Info 95" (Hellicon Publishing Ltd., UK, 1994) that states: "Of the [109] known elements, 95 are known to occur in nature (those with atomic numbers 1-95)" (page 459). Another source that includes americium to the elements that are found in nature is "The Free Dictionary by Farlex" that states: "[Americium] occurs in nature in minute quantities in pitchblende and other uranium ores, where it is produced from the decay of neutron-bombarded plutonium, and is the element with the highest atomic number that occurs in nature". This source can be found online here: http://encyclopedia.farlex.com/Americium-239 The above quote is reproduced in several other web sites, eg.: http://www.talktalk.co.uk/reference/encyclopaedia/hutchinson/m0009901.html Perhaps the confusion arises from two facts: 1) Quantities of americium (and curium) have recently been found in nature as a by-product of the operation of nuclear reactors and nuclear explosions (ref: http://www.hps.org/publicinformation/ate/q650.html). This, however, doesn't mean that americium cannot be found as a naturally occurring element as well. 2) Americium was first synthesized in 1944. The fact that it was synthesized before it was discovered as a naturally occurring element should not exclude it from the list of the elements that are found in nature. In fact, technetium and promethium are included in the list, even though they both have been artificially produced before they were found in nature. I would like to have some feedback on the topic. CostaDax (talk) 18:12, 15 February 2011 (UTC)
 * I can't access your "offline" sources, but the online one seems in order. So if you're certain of it, just be bold and change the table (Periodic table (standard)) to make Am's "natural occurrence" be "From decay". (Or maybe discuss it on the americium article's talk page as well.)--Roentgenium111 (talk) 15:35, 10 May 2011 (UTC)

Yes, atomic weights put in parrenthasies for 43, 61, 84, 85, 86, 87, 88, 89, 93, 94, 95, 96, etc.
Tc (99) Pm (145) Po (210) At (210) Rn (222) Fr (223) Ra (226) Ac (227) Th (232) Pa (231) U (238) Np (237) Pu (244) Am (243) Cm (247) Bk (247) Cf (251) Es (252) Fm (257) Md (258) No (259) Lr (262) Rf (261) Db (262) Sg (263) Bh (262) Hs (265) Mt (266) Ds (269) Rg (272) Cn (277) Uut (278) Uuq (285) Uup (287) Uuh (293) Uus (294) Uuo (294)

Also, the atomic weights of the stable elements aren't the weights of the most common isotopes.

Isotopes

Ununoctium 293Uuo 294Uuo

Ununseptium

291Uus 292Uus 293Uus 294Uus

Ununhexium

289Uuh 290Uuh 291Uuh 292Uuh 293Uuh

Ununpentium

287Uup 288Uup 289Uup 290Uup 291Uup

Ununquadium

285Uuq 286Uuq 287Uuq 288Uuq 289Uuq

Ununtrium

278Uut 282Uut 283Uut 284Uut 285Uut 286Uut 287Uut

Copernicium

277Cn 278Cn 279Cn 280Cn 281Cn 282Cn 283Cn 284Cn 285Cn

This last part is where most of the differences come in.

Isotopes in italics are the most stable isotopes. —Preceding unsigned comment added by 71.217.65.69 (talk) 06:23, 3 March 2011 (UTC)


 * I'm confused...what does this have to do with the Periodic table article? DMacks (talk) 22:06, 3 March 2011 (UTC)

Needs complete rewrite?
This page seems poorly structured and is surely incomprehensible to most people. The periodic table is a key part of understanding chemistry and is one of the earliest things one is taught, yet this article would baffle any schoolchild (and me, and I'm 42!). I've read much clearer explanations of the periodic table, and the page seems non-standard for Wikipedia. And no, I couldn't rewrite it as I don't know enough about it! —Preceding unsigned comment added by 92.14.246.85 (talk) 08:53, 4 April 2011 (UTC)
 * Could you give us some specific clues about what is confusing here, or else (even if you can't write it) some ideas about how other clearer explanations are organized? For example, do you think the current article focuses too much on some topic that is too technical, or has too much technical or historical-origin material (vs modern application) too early, or...? DMacks (talk) 12:38, 4 April 2011 (UTC)
 * And could we do away with references and pictures to Mendeleev? He only wrote part of the table in its current format, others discovered periodicity before him, such as Newlands (although only credited some years later). Ephebi (talk) 12:18, 25 May 2011 (UTC)

Strange redirect
Why does "list of groups" redirect here? I came here expecting to find a list of mathematical groups. I've never heard the periodic table being referred to as the list of groups; is it a historical name? —Preceding unsigned comment added by 82.6.96.22 (talk) 06:36, 9 May 2011 (UTC)
 * The reason is that some time ago an anonymous IP user created an article at "list of groups". However this article was found by a registered editor, who redirected it to "periodic table" because the IP's article was about the periodic table's groups: alkali metals, alkaline earth metals, and so on. Of course, this redirect is quite illogical. I'll change the target. Lanthanum-138 (talk) 12:51, 20 May 2011 (UTC)
 * Oops, there doesn't seem to be a suitable target for this case. Lanthanum-138 (talk) 15:30, 20 May 2011 (UTC)

Caption Typo
caption reads: "The table is shown to be almost circular even THROUGH most commonly it is not drawn so." instead of: "The table is shown to be almost circular even THOUGH most commonly it is not drawn so." --68.54.201.151 (talk) 03:39, 31 May 2011 (UTC)
 * Fixed, thanks. Materialscientist (talk) 03:52, 31 May 2011 (UTC)

Points on history missing
Here's the list of post-discovery points of periodic table history:


 * Original table contained 12 periods. Who and when first contracted the number by placing all elements 57-71 (not named yet) into the same cell?


 * Who and when contracted the short-periodic table to the long-periodic one (i.e. the one used now)? Something more is needed than current mentioning.


 * Point that before WWII, thorium was placed under hafnium, and uranium after tungsten, as these (not named that way then) actinides are chemically similar to the respective elements and not showing a clear trend, making "lanthanide" series unique. Element 102, for example, should be eka-polonium, and not a "actinide".


 * This is the neatest point: about 1944, when neptunium and plutonium were produced and studied, the were shown to be similar to uranium, and something we may now call "uranide" concept was promoted: elements 92-106, occupying a single cell under tungsten, like "lanthanide" one, while element 107 should be what we now call bohrium.


 * When was "actinide" (elements 89-103) concept first promoted? Who invented the lanthanide and actinide words? It was some Soviet scientist in 1948, but this is worth mentioning


 * (optional one) Why instead of original lanthanides and actinides, La and Ac started to be placed in the corresponding cells (I remember some 1950s tables, where the cell was divided in halves: first one for La and the second one for elements 58-71)? How did Lu and 103 (later Lr) started to appear there instead? What's the situation now?


 * Finally, it could be sweet to mention that some recent elements may break the existing rules on periodicity, such as 114 and 118, as well as future superactinides, you may see that in extended periodic table.--R8R Gtrs (talk) 19:48, 4 June 2011 (UTC)

I also think that the history section could be improved by mentioning some things:


 * The lanthanides or rare earth elements and the expansion of the periodic table, with an unkown number of elements. There the final fixture of the table by the measurments of Henry Moseley could be helpful


 * The missing nobel gas elements which were discovered in a short time and although the periodic table had to be redrawn they fit into the concept.


 * The change in drawing the periodic table introduced I think by Glenn T. Seaborg.

--Stone (talk) 21:21, 4 June 2011 (UTC)


 * Also, before I forget: it could be sweet to mention that 18-elements long period table is uncommon is Russia and the CIS. Groups are still most commonly called like VIA for group 16 (or sometimes group 6). Structure of table used there can be seen here.


 * Maybe it's also worth mentioning metals weren't considered chemical elements before Lavoisier's work?--R8R Gtrs (talk) 22:13, 4 June 2011 (UTC)


 * The French version of this article has some more sweet points on the history of the PT. Lanthanum-138 (talk) 06:16, 5 June 2011 (UTC)

Typo to fix
✅

It's only a minor typo, but I am not permitted to fix it myself, so... Here's something for someone who can.

"Substitution of atomic numbers, once understood, gave a definitive, integer-based sequence for the elements, still used today even a new synthetic elements are produced and studied." [emphasis added]

That "a" should be "as". — Preceding unsigned comment added by Bentsm (talk • contribs) June 6, 2011
 * Fixed. TJRC (talk) 22:33, 6 June 2011 (UTC)

arrangement of periodic table
why not just arrange the elements into a list starting with the lightest anf ending with the heaviest — Preceding unsigned comment added by 202.125.252.155 (talk) 08:17, 7 September 2011 (UTC)
 * There are certainly lists like that. But they mask many important trends of other properties of the elements. Hence, this layout helps see these periodic patterns. DMacks (talk) 08:24, 7 September 2011 (UTC)

Another typo
As before, it's a fairly straightforward typo, but I'm not allowed to fix it myself.

So, for whoever can fix it:

"Since the elements can be uniquely sequenced by atomic number, conventionally from lowest to hightest, ..." (emphasis added)

(I doubt I even need to say it, but "hightest" should be "highest".)

BentSm 19:51, 26 October 2011 (UTC)
 * ✅ -- Ed (Edgar181) 19:56, 26 October 2011 (UTC)

Edit request on 3 December 2011
Please change "The most recently named element is copernicium (number 112), named on 19 February 2010; " as two other elements have been named since Feb 19th, 2010. on Dec 1, 2011, Flerorium and Livermorium, see http://www.livescience.com/17287-element-names-flerovium-livermorium.html

Also it seems from the following article that the names for Darmstadtium (110), Roentgenium (111) and Copernicium (112), were approved by the General Assembly of the International Union of Pure and Applied Physics on Nov 4, 2011 (not in February 2010), see http://www.livescience.com/16887-elements-copernicus.html

67.193.115.51 (talk) 03:16, 3 December 2011 (UTC)


 * ❌, the names have only been proposed; they have not been officially named yet. Please note that the article that you are referring to says that they will be officially named in five months. Also, while the International Union of Pure and Applied Physics just accepted the names for use, the International Union of Pure and Applied Chemistry has accepted them for quite some time. I thank you for wanting to help the encyclopedia, however, and if you have any other suggestions, please feel free to ask again. Thank You. StringTheory11 (talk) 03:54, 3 December 2011 (UTC)

Correction of the first sentence is needed.
I find that statement in the first sentence of the article stating that the elements in periodic table are " organized by selected properties of their atomic structures" is not factually accurate. The elements in the traditional periodic table are organized in accordance with chemical properties and, for the most part, ignore the atomic structure. The atoms comprise electronic shells, which correspond to energy levels depicted by the quantum number n=1,2,3,4.... and sub-shells, corresponding to orbital angular momentum, quantized by the quantum number l=0,1,2,3,4 and reflected by the blocks of the periodic table. While only first two periods of the periodic table reflect the electron shells and the quantum number n, the blocks of the periodic table are placed in peculiar order: 0,2,1 plus 3 (which is added as a footnote). So, what other "selected properties of the atomic structures", besides the atomic number, are actually reflected in traditional periodic table? The answer is none. The article has to be corrected. Drova (talk) 16:02, 19 December 2011 (UTC)


 * ❌, unfortunately, you are wrong here. The periodic table is completely organized by the filling of the orbitals. As a result, atomic number is represented in the table, but only incidentally. The table is not organized by atomic number, but by electron configuration. Note that there ARE other properties reflected, which are detailed in the organization section, but these are all by-products of its organization by subshells. The blocks are placed in the order they are since each time a new shell is started, a new period is started as well. Thank You. StringTheory11 18:01, 19 December 2011 (UTC)


 * I looked at the "organization" section but did not find anything there on the properties of the "atomic structures" of the elements, except mention of the atomic numbers. Instead I found confirmation that the periodic table is organized in accordance with the chemical properties. If the table was "completely organized" in the order of the filling of orbitals (see Madelung Rule and Aufbau diagram) then periods would begin with the introduction of new orbitals and end with alkaline earth metals, just as in Janet's Left Step Periodic table, that is also called spectroscopic periodic table. The argument that blocks are placed in the order corresponding to the beginning of the new shells is flawed, since shell identification is not maintained from block to block within the periods and periods do not end with the closure of the shells. Instead, the periods end with the completion of p-orbital, corresponding to l=1. For example, filling of third shell ends with Zn and d-electron, but Zn, along with 13 preceding elements, is placed within the fourth period, not at the end of third period! Fourth shell ends with Yb and f-electron, which is placed in the first line of the little footnote table corresponding to the 6th period in the long version of the PT. Also, article states that all gaps are closed, but anyone can see huge gaps between H and He, B and Be, Mg and Al. What those gaps represent? The gaps are there because new orbitals are introduced after alkaline earths. So, the alkaline earths should mark the end of the periods and s-block should be the last, if order of orbital filling was a concern. This would correspond to l = ...,3,2,1,0 quantum number order. The gaps are there also because properties of the elements within the groups have to match. The reason for such organization of traditional PT is desire to begin periods with metals, then proceed to non-metals and to end them with noble gases, and not the atomic structure.  Drova (talk) 01:02, 20 December 2011 (UTC)


 * OK, you are missing an important point here. The reason the table starts with the s-block is that the s-block is the first time that a shell is being filled (e.g. the first time the fourth shell out from the nucleus has an electron in it for a neutral, non-excited atom is at potassium, an alkali metal.) Therefore, the periodic table is just organized by orbitals in a different way than the Janet periodic table. The periods just happen to end with the p-orbital because the next orbital filled after that is in the next shell. Even though the quantum number order is not in sequence, the table still is organized in relation to atomic orbitals. The f-block and d-block are in the places they are because they have a higher energy level than the the s-block that is in their row (e.g. the 4f shell is after the 6s shell because the 4f shell has a higher energy than the 6s shell, and the 3d shell is after the 4s shell because the 3d shell has a higher energy than the 4s shell.) StringTheory11 03:32, 20 December 2011 (UTC)


 * How can you argue that the periodic table is based on atomic structure when you take in account only points where periods begin and completely ignore what happens next. Fact is that periods in traditional Periodic Table do not correspond to the electron shells, period. Why should we care then whether they start in the beginning of the shells or not? Madelund rule states that orbital filling happens in accordance with n+l, which is combination of energy and orbital momentum. The rule is established experimentally and based on spectroscopic signatures of the atoms. The energy increase occurs with the decrease in orbital momentum. When orbital momentum of electrons reaches its minimum at l = 0, energy is in its highest point, then the value of the orbital momentum abruptly jumps to a higher value while corresponding energy drops down (or stays at its maximum for the first three periods). This gets repeated again and again, in periodic manner. Assumption that periods must start with first electron in sub-shell "s" is based on common mistake that energy and orbital momentum increase in the same direction, that is n=1,2,3... and l = 0,1,2,3.... But Madelung rule establishes different order: n=1,2,3... and l =....3,2,1,0. That is l begins with maximum and ends at zero. Therefore, periods must end with the last electron in s sub-shell, not begin with the first. Traditional Periodic Table layout was first introduced by Alfred Werener in 1905, when no one knew what the atomic structure was. It is based on termination of the periods at noble gases.Drova (talk) 15:20, 20 December 2011 (UTC)


 * The periods in the periodic table do correspond to electron shells. I will state this again: A new period is started when a new shell is first being filled. The atomic structure part is a nice by-product of the layout, but is not how it is organized. The periods are organized in order of energy, with a new period started when a new shell is being filled (not a new subshell, but a new shell.) If you want an example showing that this is true, take a look at extended periodic table. The article says that different elements may occupy the s-block of the 9th period than would be expected, simply because of their electron configuration. If you can find a source that says the periodic table was initially based on termination at noble gases, by all means insert that into the article, but nowadays a new period started when a new shell starts to be filled. StringTheory11 18:09, 20 December 2011 (UTC)


 * Lets examine forth period, for example, to see how many elements corresponds to the forth electron shell. Characteristic electrons of K and Ca fill forth shell, Sc through Zn mark filling of third shell and Ga through Kr - fourth shell again. Things are getting more complicated beginning with 6th period, where most elements do not correspond to shell number six. Energy levels are not constant within periods also, since periods include elements with characteristic electrons corresponding to various values of "n". If you want example of periodic table that truly mimics electron structure of atoms and where energy levels are not mixed up, see ADOMAH Periodic Table presented among Alternative Periodic Tables. It mimics electron structure of Ubn (Z=120) in its entirety. You can even derive electron configurations without any reference to Aufbau mnemonic using that table. Regarding history of traditional Periodic table, I recommend J.W. van Spronsen "The Periodic System of Chemical Elements. A history of the First Hundred Years", 1969, which is not listed in your bibliography.Drova (talk) 20:12, 20 December 2011 (UTC)


 * The reason that Scandium through Zinc are in the fourth period is that the 3d electron shell has a higher energy than the 4s shell. However, the 4p shell has a higher energy than the 3d shell. The table is arranged by electron configuration, from lowest energy (the 1s shell) to highest known energy (the 7p shell.) Again, periods are started when a new shell is started, a logical choice for the table. The ADOMAH periodic table also organizes the elements by electron configuration, but in a slightly different way; it starts with the 4f, for example, and goes to the 7s, which is the way you are describing. This is by no means wrong, but is simply a different way to organize by electron configuration. You can derive electron configurations by using the normal table as well. The reason that elements are between the s-block and the p-block (this is what I assume you mean by "squished") is that the orbitals being filled in those elements have a higher filling energy than the s-block, but lower than the p-block. Similarly, the f-block has a higher energy than the d-block. StringTheory11 21:12, 20 December 2011 (UTC)


 * Please, refer to fig. 9.4 in Scerri's book "The Periodic Table. Its Story and Its Significance", listed in the bibliography, that demonstrates example of transition between elements in s-block and d-block. This figure shows that in K and Ca, located in s-block, 4s orbital has lower energy than 3d-orbital, but in Sc, that is located in d-block of the periodic table, 3d orbital has lower energy than 4s. Also, in all transition and rare earth metals, s-electrons ionize first. Energy aside, number of elements in periods of traditional periodic table is 2,8,8,18,18,32,32 and number of electrons in first seven shells are 2,8,18,32,32,18,8. This demonstrates obvious disconnect between lengths of periods of traditional Periodic Table and the size of electron shells, as well as disconnect between the structure of traditional periodic table and the electronic structure of the atoms.Drova (talk) 11:45, 22 December 2011 (UTC)


 * There can only be 2 electrons in the 4s orbital, so of course the 3d orbital has lower energy than the 4s orbital when the 4s orbital is filled. Also, the reason that the number of electrons are 2,8,18,32,32,18,8 is simply that the elements that in order to balance it out, the energy levels of all subshells in the shells would have to be equal, which is simply not true. StringTheory11 17:57, 22 December 2011 (UTC)


 * On December 21 you posted following: "...Scandium through Zinc are in the fourth period is that the 3d electron shell has a higher energy than the 4s shell.". Today you seem to agree with me that in Scandium: "the 3d orbital has lower energy than the 4s orbital when the 4s orbital is filled." I think that we are on the same page now. You also agree that number of electrons in shells 2,8,18,32,32,18,8. I think that you do not dispute that, beginning with third period, length of periods in traditional periodic table (2,8,8,18,18,32,32) does not correspond to the number of electrons in shells, that is 8 is not equal 18, 18 is not equal 32, etc. Regardless the reason(s), the fact is that, for the most part, traditional periodic table does not follow the structure of atom. Therefore, instead of saying that elements are "organized by selected properties of their atomic structures" I suggest following language: "Periodic table is a classification system that seeks to classify chemical elements. The placement of elements in the periodic table is based on chemical and physical properties of atoms. Theoretical justification for the periodic system is provided by quantum mechanics", or something like that. Drova (talk) 23:29, 22 December 2011 (UTC)


 * What I am saying is that the first two electrons in the 4s orbital have a lower energy level than the 3d orbital. However, to put a third electron in the 4s shell is impossible, and therefore the 3d orbitals have a lower energy than having a third electron in the 4s shell. I do not dispute that the period length does not correspond to the number of electrons in a shell; the reason for this is that, as a rough estimate, the more "complicated" shells have an energy just lower than the energy of the more "simple" shells in a shell one higher (sorry if this sounds confusing, but I can't think of a better way to say it.) The traditional periodic table does follow the structure of the atom, but in a different way than what you are thinking of; it is ordered by filling energy of the subshells, with a new period starting whenever a new shell is started. StringTheory11 00:24, 23 December 2011 (UTC)


 * You concentrate on adding electrons/protons thus generating new atoms. I concentrate on ionization of previously formed atoms. Scerri also writes on p.236 that 4s electrons are overall less stable since they, rather than 3d electrons, are more easily removed. Of course in atom of Ca 3d orbital has higher energy than 4s orbital, that is why Ca belongs to s-block. There are no 3d electrons in ground state Calcium atoms. But in Scandium 4s electrons are more energetic than 3d electrons. Allow me to quote Scerri again. He writes on page 236 following: "In considering the buildup of atoms across the periodic table, one is concerned with successive addition of one proton and one electron to each previous atom. However, in considering the ionization, one is concerned only with the successive removal of electrons and not the removal of protons." However,I would like to add that addition of one proton/electron pair does not occur in nature. Such "process" is a product of human imagination. This is not how new atoms are synthesized. Sc atoms have 21 protons/electrons where 4s electrons have higher energy than 3d electrons. That is why 4s electrons (first two valence electrons in Sc) get removed first and captured last by the nucleus with 21 protons. You do not find ions of Scandium with two s-electrons filling 4s orbital and d-electron missing, but ions with missing s-electrons and 3d electron in place are common. Perhaps I could agree that traditional periodic table follows electronic structure to some degree, very loosely though. Otherwise it would not be periodic at all. However, it is quite a stretch to claim that the periodic table is organized on a basis of the atomic structures. Can you please quote a source or two to back up your strong opinion regarding this issue? Drova (talk) 05:54, 23 December 2011 (UTC)

One source, referenced in the article: "Once the significance of atomic electronic configurations was realized, the table was adapted to be almost completely consistent with them, from [Leigh, Jeffery. "Periodic Tables and IUPAC". Chemistry International: The News Magazine of The International Union of Pure and Applied Chemistry (IUPAC). Retrieved 23 March 2011.] or ref #9 While this doesn't explicitly state my point, I feel that it strongly implies it. Another quote from a source is: "Now Pekka Pyykkö at the University of Helsinki has used a highly accurate computational model to predict electronic structures and therefore the periodic table positions of elements up to proton number 172 - far beyond the limit of elements that scientists can currently synthesise, from [Extended elements: new periodic table". 2010.] or ref #16. This more explicitly states my point than the last one. StringTheory11 06:59, 23 December 2011 (UTC)


 * I am aware of Pyykkö's work and his periodic table, but he could fit results of his calculations in almost every available alternative periodic layout, being it spiral, round or pyramidal. Periodic System has always been one, but it can be presented in thousand different ways. He chose traditional PT layout because of its popularity, not because his calculations prove that traditional periodic table better reflects atomic structure than other layouts. Frankly, I do not understand why you brought up this example. It does not seem to strengthen your point. I can also agree with Jeffrey Leigh that traditional periodic table is consistent with electron configurations, just as almost all other alternative layouts, being spiral, round or pyramidal. But if one had a goal to construct periodic table based strictly on atomic structures, without any regard to element properties, he or she would most likely come up with Janet's LSPT-like system. "Minimum Chemical Data Reqired for Construction of the LSPT..." and "connections with atomic physics are what make the LSPT 'right'..." (Henry Bent. "New Ideas in Chemistry from Fresh Energy for the Periodic Law"). Traditional periodic table was first created on a basis of chemical properties. But guess what? Chemical properties are related to atomic structures of atoms! Only later it was realized that traditional layout is also "almost completely consistent" with them. It is easy to make such statement now, looking back, but if one would set the goal to build periodic table from scratch on a basis of atomic structures of the atoms only, without regard to chemical properties, it is highly, highly unlikely that one would come up with the traditional layout. Drova (talk) 13:40, 23 December 2011 (UTC)


 * Note that it was said that Pyykkö came up with "a highly accurate computational model to precdict electronic structures and therefore the periodic table positions of the elements up to proton number 172." Because electronconfigurations are what Pyykkö used to predict the positions of the elements, especially ones that have completely unknown chemical properties and are likely to be completely different than what we know, it reasons that the periodic table is organized by electron configurations. StringTheory11 20:34, 23 December 2011 (UTC)


 * And yet the anomalous electronic configurations of elements such as chromium and copper, not due in any obvious way to the spin-orbit coupling that is the basis of Pykko's predictions, has to be taken into account here as well. Nobody doubles up copper and zinc in the same position in the chart, leaving a blank space- but that is what one would need to do for the depiction to be entirely consistent with electronic configurational organization. The problem is that there are distinct levels of motivation here. A Janet left-step system, as well as other 2 and 3D patternings can capture in the simplest possible way what the electronic configurations WOULD be sans effects from spin-orbit coupling, differential shielding, the particulars of proximity of energy levels, and so on. The counts and orderings from quantum mechanics alone are internally consistent as an organizing principle. The others, not so much, since we know that orbitals don't react the same way (some expand, some shrink) to increasing relativistic velocity. Adding spin-orbit coupling messes things up much more. But all these are DERIVED, interactive traits- the only ones that change in a regular, linear way are atomic number, the principle quantum number, straightforward relativistic velocity, and shielding efficiency. Even Madelung's rule seems to be derived. 67.81.236.32 (talk) 15:51, 24 December 2011 (UTC)


 * I agree with you on many points here. The left-step system would be the most accurate if electron configurations always followed the Madelung rule. However, since they don't, we have to use this table, which is primarily based on electron configuration, with a couple ambiguous cases (e.g. Cu, Zn) just put in numerical order for consistency. Take a look at extended periodic table; it may help ease some confusion. StringTheory11 19:13, 24 December 2011 (UTC)


 * Surprise! Traditional Periodic Table is periodic because it follows Madelung rule! The reason why lengths of periods in the periodic table recur is the n+l rule! If periods followed electron shells without regard to n+l rule their length would be 2,8,18,32.... and not 2,8,8,18,18,32,32...You do not have to believe me. Please, go to page 233 of Scerri's book "The Periodic Table. Its Story and Its Significance" that is listed in your bibliography, where you can read following: "The assignment of electronic configurations to the atoms in the periodic table proceeds according to three principles: 1)Aufbau Principle: Orbitals are occupied in order increasing values of n+l..., 2)The Hunds principle: when electrons fill orbitals of equal energies, they occupy as many different orbitals as possible; 3) The Pauli exclusion principle. I am providing this reference again, even though all my previous attempts to provide solid references were simply ignored. However, if opinions of the scientists quoted by me were taken seriously, one would observe that Pykko's "highly accurate computational model" first and foremost confirms the validity of the Madelung rule. All periodic table layouts, including the left step and the traditional periodic table FOLLOW MADELUNG RULE! Only Left Step table does it more closely, without regard to the properties, while the Traditional Periodic Table differs from it only because it separates metals from non-metals. The Madelung rule is one of the reasons why all groups in traditional periodic table, as well as in Pyykkos extended table, coincide with the groups of the Left Step table. Drova (talk) 02:15, 25 December 2011 (UTC)


 * I do not have the book and do not have a library card, so cannot get the book to look at. I am not saying the Madelung rule is invalid, and I agree that they all follow it. I still am not sure why you insist that left step does it more closely; they are just different ways of doing it, neither is "better." StringTheory11 03:17, 25 December 2011 (UTC)


 * I insist because I studied that book as well as other books on this subject very thoroughly, to the point that I made my own humble contribution and earned honor to be regarded as an expert in the subject of the periodic law by the authors of the last two books that I quoted, as well as by other scientists in this field. So, I quote Eric Scerri again (p.286, 2007): "The left step table, I suggest, embodies the elements entirely as basic substances since it relegates the chemical and physical properties of elements such as Helium and places greater importance upon more fundamental aspects. From a philosophical point of view, I believe that the left step table may provide the optimal periodic system in showing the greatest degree of regularity while also adhering to the deepest available principles relating to the elements as basic substances." I could provide many more quotes like that, from different authors. I am not in the business of misquoting books of others. For complete explanation why I insist that left step does it more closely you need to read books that I quoted above. As well as Philip Stewart's latest article on this subject in Foundations of Chemistry. Drova (talk) 03:57, 25 December 2011 (UTC)


 * I do not disagree with you that the left-step periodic table is optimal: I think it may be marginally better than the standard layout. However, since the standard layout is what is approved by the IUPAC, we use it in wikipedia, and it is not inaccurate by any means, just a different way of showing things. StringTheory11 06:45, 25 December 2011 (UTC)


 * Thanks. I understand that the article is about standard layout approved by IUPAC. That is not the issue. IUPAC is organization that is mainly concerned with pure and applied chemistry. That is why their choice of periodic table layout is based first and foremost on chemistry and chemical properties of atoms. As I wrote above, the periodic table in its traditional form was first introduced in 1905, when structure of atom was not known and it was organized purely on a basis of chemical properties of the elements. It remains as such to this day. When electronic structures of atoms became known, thanks to spectroscopy and quantum mechanics, it was observed that the layout of the elements in traditional table is "almost completely consistent with them". Therefore, to claim that traditional periodic table was organized on a basis of atomic structures is historically and factually incorrect. Therefore, first sentence of the article must be corrected at once. Drova (talk) 12:31, 29 December 2011 (UTC)


 * You two guys are having an admirable discussion about the relative merits of the 2 (best?) periodic table formats based on electron shell filling while at the same time missing the point about the physical structure of the atomic nucleus. To help in understanding this problem I recommend that you purchase about 24 of the 3/8 inch diameter Neodymium cylindrical magnets and try to accumulate them into a structure and see what they tell you. The first 4 magnets will build you a planar structured alpha particle. And the second 4 magnets will build you an 8 magnet cube representing an atom of EE4Be8. Never mind that it is stable where EE4Be8 is not because they're not spinning. Then comes the important point! The next 4 magnets will build a nucleus of a EE6C12 atom, Which Gamow says can happen, but not in a 3 planar configuration, but rather with 2 deuterons on either side of the 8 magnet cube. Then the next 4 additions of 2 magnet deuterons bring the structure up to the 8 magnet cube with 6 deuteron magnets wrapped around it to make EE10Ne20. And that's what the Janet periodic table is trying to tell you. And you don't get a third planar alpha particle within the nucleus until you add 4 more magnets on the top of the atomic structure to make EE12Mg24. And please at least build this structure and look at it before categorically denying it's indicating possibilities. So each period ends with the accumulation of an additional planar alpha particle in the center on the top. And each exposed (N for north and negative) magnet end is a potential location for the addition of an additional "extra neutron" to the structure in a manner as to best create and/or maintain the dynamic balance of the structure against rotational and other dynamic stresses.WFPM (talk) 16:12, 11 April 2012 (UTC)
 * This is an interesting discussion (although I think the 'first sentence of the article' has long since been fixed). What I would say is that we should never forget that empirical observations of the elements' properties come first, and are 'real', whilst theoretical models are not - they are just made up :) There's not really any such thing as 'electron shells', for instance (that just a simplification of quantum mechanics, using the 'orbital approximation' to make the maths easier). If you look at real properties of real elements (compare carbon and tin? boron and thallium?) you'll appreciate that the empirical reality is a lot messier than a over-simple reliance on models to categorise and arrange things. --feline1 (talk) 08:33, 13 April 2012 (UTC)


 * That's right! And when you get into theories about electron shells, you're getting into what I call a "theory about a theory". And away from the concept of the atomic nucleus as a real 3 dimensioned physical entity. And so the models are not perfect, but at least they're 3 dimensional real physical models with volume and configuration and magnetic force properties. So they should be built and analyzed rather than being dismissed out of hand. And they bring up the point that nature didn't have a lot of diversity to work with when the universe was beginning, and the question becomes as to how it is being worked out. I hope you have read my contributions to Talk:Charles Janet, as to how the periods of the Janet periodic table can be subdivided into equal retained free energy subdivisions due to the nature of the accumulation process. You can also note that beyond the modeling of EE12Mg24 (with zero excess neutrons), you can splurge on 16 additional magnets and repeat the last 8 accumulation steps and arrive at a model of EE20Ca40 which is the last nucleus that is stable with zero excess neutrons. And after that you have to get more involved with the stability factors related to the proper adding of excess neutrons (like 3 for OE21Sc45 and 5 for OE23V51 and for 4 for the other transition elements except for EE28Ni58, which gets by with only 2). And for that you need to study the individual element stability profile charts and associated data.WFPM (talk) 18:05, 13 April 2012 (UTC)


 * OK - but don't forget subatomic particles such as protons and neutrons are just a theory too (Albeit, a pretty good one that had a lot of 'explanatory power'...)  But I find it worrying when people say things like "the elements obey the Madelung rule" or whatever - no they don't!!! It's the Madelung rule describes the elements!! And if the elements behaved differently, the Medelung Rule would have to be changed...--feline1 (talk) 19:40, 13 April 2012 (UTC)


 * You're right again! Because when we get to the Madelung rule were talking about a theory about a theory about a theory! And whereas I can see the dynamic problems related to the equalization of velocities and compatibility of spin properties of adjoining nuclei, particularly when they are not permitted to come into contact, I don't see how anybody can come to a firm conclusion about anything except through models and experimenting. That's why I would like to see what a quantity of OE9F18 would do if it were cooled to Zero degrees Kelvin. But nobody wants to answer my question. And because when I studied casualty concerning failure modes, the idea that I got was that failures were due to binomially distributed random deficiencies of product manufacture during the initial period, after which time the remaining good units could have an indefinite working life period. And the idea that because a few EE62Sm146 atoms want to change to EE60Nd142 doesn't necessarily mean that all the EE62Sm146 atoms are necessarily unstable. That's why I'm afraid of some of the mathematics of this nuclear physics stuff. But of course we have to have theories and reliable methods of communication. And we have the standard model, and National Geographic's May 1985 article on the atom and graphic model of the EE6C12 atomic nucleus which I think is wrong and thus leading us astray.WFPM (talk) 00:10, 14 April 2012 (UTC)