Talk:Periodic table/Archive 2

From Wikipedia, the free encyclopedia

Archive This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.

Contents

Suggestions

Does anyone want to list the oxidation states on a certain periodic table? Bensaccount 02:23, 13 Apr 2004 (UTC) I think the table needs to completely be replaced by something more orderly. The valence electron spots are off.

Anyone know of a good Periodic spreadsheet. The best I could find was this: http://www.shopinberkeley.com/science/tools/.


Naturally occuring elements

If we assume that wikipedia a reliable source, then we have:

Technetium

"Once it was available in macroscopic quantities i.e. enough to determine its chemical and physical properties, it was discovered to exist naturally elsewhere in the universe. Some red giant stars (S-, M-, and N-types) contain an emission line in their spectrum corresponding to the presence of technetium. Its presence in red giants has led to the establishment of new theories about the production of heavy elements in stars."


Promethium

"Promethium does not naturally occur on earth, but has been identified in the spectrum of the star HR465 in Andromeda."


Neptunium

"Trace amounts of neptunium are found naturally as decay products from transmutation reactions in uranium ores."

Plutonium

"While almost all plutonium is manufactured synthetically, extremely tiny trace amounts are found naturally in uranium ores. These come about by a process of neutron capture by 238U nuclei, initially forming 239U; two subsequent beta decays then form 239Pu (with a 239Np intermediary), which has a half-life of 24,100 years. This is also the process used to manufacture 239Pu in nuclear reactors."


Externally we have:

Technetium

http://periodic.lanl.gov/elements/43.html

"Technetium has been found in the spectrum of S-, M-, and N-type stars, and its presence in stellar matter is leading to new theories of the production of heavy elements in the stars."

http://www.webelements.com/webelements/elements/text/Tc/geol.html

"Technetium has been found in the spectra of S-, M-, and N-type stars, but is not found in earth's geosphere."

Promethium

http://www.webelements.com/webelements/elements/text/Pm/geol.html

"It appears that there is no known Pm existing in the earth's crust other than in very small quantities in uranium ores where it is present as a uranium decay product."

http://periodic.lanl.gov/elements/61.html

"Promethium, however, has been identified in the spectrum of the star HR465 in Andromeda. This element is being formed recently near the star's surface, for no known isotope of promethium has a half-life longer than 17.7 years."

Neptunium

http://periodic.lanl.gov/elements/93.html

"Trace quantities of the element are actually found in nature due to transmutation reactions in uranium ores produced by the neutrons which are present."

http://www.webelements.com/webelements/elements/text/Np/geol.html

"Trace amounts of neptunium are present in uranium ores."

Plutonium

http://periodic.lanl.gov/elements/94.html

"Plutonium also exists in trace quantities in naturally occurring uranium ores. It is formed in much the same manner as neptunium: by irradiation of natural uranium with the neutrons which are present."

http://www.webelements.com/webelements/elements/text/Pu/geol.html

"Plutonium is found in trace quantities in uranium ores but, in practice, normally it is synthesised by the transmutation of uranium."


Also, why did you revert the change I made to Gallium when your objections were only about naturally occuring elements?

Darrien 09:44, 2004 Apr 25 (UTC)

Read Synthetic element: "The chemical elements labelled as "synthetic" are unstable, with a half-life so short (from a few million years to a fraction of millisecond) relative to the age of the Earth that any atoms of that element that may have been present when the Earth formed have long since completely decayed away." You are reading the word synthetic way too literally. None of the elements you cited are found in any significant amount in the Earth's crust. They are therefore synthetic and are almost always depicted as such in other periodic tables.geology.gov.yk.ca, education-india.net, www-tech.mit.edu Gallium melts at 85.57 °F. It is therefore solid at STP. --mav 10:30, 25 Apr 2004 (UTC)
I understand the difference completely. They way the grouping criteria were described is what you seem to take issue with.
The article never said anything about elements being liquid at STP. If your intention was to classify the elements' phase at STP, then state it.
I've reworded the criteria in a way that I feel more clearly describes your intended grouping.
Darrien 11:03, 2004 Apr 25 (UTC)
Yes - much better. I updated bromine to fix its solid/liquid issue as well. --mav

Lanthanides and Actinides (Inconsistency)

Traditionally, the periodic table classifies the lanthanides (#57-#71) and the actinides (#89-#103) as Group 3 elements and put them under the two boxes under yttrium (#39), then spell out ther series below the whole table. Periodic table (anti) follows the convention. (Note: the current table has been changed. This is the table I am referring to: Old periodic table (anti))

The table on the main page: Periodic table, however, kicks lutetium (#71) out of the lanthanides and lawrencium (#103) out of the actinides. Periodic table (wide) shows a similar opinion: it does not color those elements with their series.

Concerning blocks, Periodic table (extended) considers La (#57) and Ac (#89) as d block, but Lu (#71) and Lr (#103) as f block. Periodic table (block) considers La (#57) and Ac (#89) as f block, but Lu (#71) and Lr (#103) as d block.

Also, for the table images of elements, some color Lu (#71) and Lr (#103) with their series, some do not.

Before we attempt to fix those inconsistencies, I would like to open (or re-open?) a discussion to reach a concensus on how to treat the lanthanides and actinides series.

Felix Wan 2004-07-04 00:12 (UTC)

Theoretically, you should be able to reassemble the periodic table based only on the electron configurations of the elements. With this ideal in mind, you should see that Lu has a full f shell, and has placed one electron into it's outermost d shell. The same is true if Lr. Because this follows the same pattern as all the other blocks (full previous shells and being filling the current block's shell (i.e. boron has a full s shell and has 1 electron in the p shell and thus is in the p block, or yttrium has a full s shell and one electron in the d shell, so it is in the d block)), it is logical that Lu and Lr are placed into Group 3.
The trouble arises when you realize that the filling of electron shells is imperfect. Both La and Ac have full s shells and one d electron, just like the other two elements in Group 3. So scientists had a problem, since both La and Lu had one d electron and full previous shells (s and f respectively) (the same happens with Ac and Lr).
Many tables have chosen to wash their hands of the whole thing and not include either La or Ac in Group 3. Others have placed one or the other in Group 3. Yet, you can still make sense of the issue. As the number of the element increases from Ac or La, the d electron often disappears and goes into the f shell. However, both Lu and Lr have full f shells AND full s shells, allowing the electrons they add to the d shell to remain there. Additionally it is the pattern to have ALL previous shells filled in order for an element to be part of a block (an element is only in the p block if both the d shell and the s shell is full).
Lastly, and possible most importantly, Lu and Lr have full f shells AND have added beyond them. In all other cases once an element completes its shell, the next one is in the next block, just like Lu and Lr. In my opinion (and the opinion of the other people in the site... apparently) it is most logical that both Lu and Lr are part of the f block, not the f block. --Ctachme 02:08, 18 Sep 2004 (UTC)

Thank Ctachme for the comments on classifying Lu and Lr as d block elements. But for the definition of lathanides and actinides, my question is this: should we make the decision on how the periodic table should look like, or should we record the periodic table most widely accepted by the Chemistry community and the public?

It appears that the tendency of excluding Lu from the La series and Lr from the Ac series in Wikipedia is unconventional. Experts in Chemistry please comment. My opinion is that we may classify Lu and Lr as d block elements, but should include them whenever we mention the La series or the Ac series to follow the convention.

Felix Wan 09:25, 18 Sep 2004 (UTC)

Since IUPAC is the official body of chemistry and such, I think it would be understandable for such a change to take place. I suspect that a debate about this has already taken place somewhere (and resulted in the current version), though I haven't actually seen it. Either way, if no one else comments on this issue, and you do want to change the table to the current IUPAC version, keep in mind that there are many different versions of the periodic table on wikipedia (see the footer) and that you need to change them all so they all are constant, don't just change a couple. --Ctachme 18:58, 18 Sep 2004 (UTC)

I've changed several tables to conform to current IUPAC naming conventions, along with definitions of lanthanide and actinide. I probably missed a few things here and there. Please correct them when you see them. Flying Jazz 02:06, 23 Jun 2005 (UTC)

A few people have been changing these tables back. The periodic table is a convention, and unless that convention is changed by IUPAC, an encyclopedia should report the convention as it actually is, not as it "should be." In terms of f-block and d-block elements, the conventional periodic table may be thought of as "chemically incorrect," but in terms of placing all group 3 period 6 lanthium-like elements together, it seems "correct enough" so the convention probably won't change in the near future. More importantly, if you are asked "is lutetium a lanthanide?" and you answer "no," you will be wrong because people still call lutetium a lanthanide. See periodic table and s, d, f-blocks according to IUPAC Flying Jazz 06:10, 24 Jun 2005 (UTC)
The IUPAC body does not have a convention on formatting! The IUPAC only does things like pick the name of elements, and make sure the values are correct. They even have an educational division but the IUPAC does not have a convention for formatting. So stop using the IUPAC to justify your setup and find another reason for aranging the data like that. My reason is that Lu and Lr belong to group three but the other lananides and actinides don't. Lanthanide and Actinide both say that they don't inlcude Actinium or Lanthanium. --metta, The Sunborn 14:18, 24 Jun 2005 (UTC)
Group 3 contains all of these elements. See Group 3 element. The IUPAC does not have formatting conventions, but it does pick naming conventions for groups of elements. See bottom footnote here and see page 8 here for these recommendations about Lu, Lr, La, and Ac. If you have a table that has "lanthanide" and "actinide" groups placed together then it is a naming convention, not a formatting convention, about which elements are placed in those categories. If you have a table with "d-block" and "f-block" groups arranged together, then the formatting would place Lu and Lr up in the d-block. Again, the naming conventions justify the formatting and if you say Lu is not a lanthanide then, according to IUPAC, you are incorrect. Flying Jazz 14:39, 26 Jun 2005 (UTC)
Even so, that only limits the colors used for the Lr, Lu. So even then we can present the table any way we as long as we don't call Lr, Lu transition metals and still keep within IUPAC lines. --metta, The Sunborn 18:16, 26 Jun 2005 (UTC)
You're right that a table that sticks with naming conventions can be presented and formatted in any way. If Lu and Lr are kept above and just their color is changed then there would be the lanthanide/actinide rows at the bottom and one additional lanthanide and actinide colored element up with the main part of the table, and this would fit IUPAC naming conventions...but a row labelled "Lanthanides" would mean to many reasonable people not paying attention to colors that all lanthanides are in that row. Helium as an s-block element placed with p-block elements because it's a noble gas is (in a naming/formatting way) like Lu as a d-block element placed with f-block elements because it's a lanthanide. Periodic table (block) makes this clear. Flying Jazz 28 June 2005 08:24 (UTC)



The element naming controversy

(This isn't about this actual article, but it involves several of the element pages so I'm putting it here.)

On all the discovered-but-unnamed element pages (111 through 115) is the boilerplate sentence, "There is an ongoing element naming controversy over what this element should be called." Really? Is the name of all of these elements under dispute? The article referenced says that the element naming controversy involved elements 104 through 108 and moreover was finished in 1997. I suspect that the sentence above is being put onto every such page without regard for whether any controversy is actually occurring about the element name. Eric119 06:30, Jul 4, 2004 (UTC)

Well, since nobody's responding, I think I'll go and revise the sentence out of the articles. Eric119 01:56, Jul 31, 2004 (UTC)

Synthetic / natual elements

I read it my Chemistry for Engineers textbook last semester that plutonium is not purely synthetic, there are about 10 grams of primodial Pu on the planet earth right now. I can show you the calculations. Neptunium might also therefore be natural because it is lighter than Pu. Technetium is noted on its article to be naturally occuring. I will quote: In 1962, technetium-99 was isolated and identified in pitchblende from Africa in very small quantities. I also read that Technetium is naturally occuring in Molybdenum mines. As such, there is at least two errors. IUPAC might list these as synthetic, however, until their reasons for synthetic qualification are revealed we should consider these elements naturally occuring. --metta, The Sunborn ☸ 17:41, 1 Oct 2004 (UTC)


I looked into this and found that the IUPAC does not list what elements are synthetic and which are not. I guess it seems that everyone whould no or not care. It seems to be on every periodic table I see and yet doesn't serve any purpose. I guess that is why no one else noticed they are wrong--it doesn't matter. --metta, The Sunborn ☸ 08:08, 20 Nov 2004 (UTC)

Most obtuse editing

The house style of a certain scientific journal required Periodic Table to be spelled with capital initial letters. So an author, writing about periodic motion of a table, referred to "the Periodic Table motion", and accordingly the capitals were inserted. Michael Hardy 03:06, 3 Nov 2004 (UTC)

5g subshell?

can someone clarify what the 5g subshell is doing in that chart? to my knowledge, it doesn't exist. Sasquatch 22:07, 31 Dec 2004 (UTC) Edit: Actually, for that matter, what's the 8th period doing in there?

Both the 8th period and the filling of 5g subshell are theorectical extensions. See Periodic table (extended). -- Felix Wan 00:13, 2005 Jan 1 (UTC)
But does it really apply to the current model of the periodic table? Just seems kind of sketchy to me that the table only has 7 periods and yet your still listing the extensions of quantum mechanics under it when the period doesn't really allow for it so it wouldn't really apply. Anyways, just thought it rather confusing. Sasquatch 10:29, 2 Jan 2005 (UTC)
The subshells are all equally sketchy. No person has ever seen one, detected one or otherwise cares if they really exist or not. Subshells are a mathematical construct and not a good scientific theory. ---The Sunborn
The spectrographers of the 1800s could "see" them. Named them Sharp, Principle, Diffuse, and Fine I think. Vsmith 21:57, 14 Jan 2005 (UTC)
Aren't the subshells just an extension of quantum mechanics? I thought they changed the model of the set energy levels because quantum mechanics says there's only a probability of finding electrons at certain places which is why they created these and they do help to explain the properties of certain compounds such as benzene Sasquatch 05:00, Jan 14, 2005 (UTC)

If not for the 8th or 9th energy levels or (or perhaps the 5g ...) where would an excited electron from radium go? Doesn't radium have an emmission spectrum? Vsmith 21:50, 14 Jan 2005 (UTC)

all the orbitals are always "there", even when they are not occupied. Even hygrogen atoms "have" vacant 5g orbitals which the electron could jump "into". Orbitals are not, however, physical containers or little rollerskate rinks, they are merely a description of electron energy & angular momentum: if an electron has a certain energy & angular momentum, we say it is "in" that corresponding orbital. However, the notion of separate orbitals is an approximation - the more nuclear charge you have, the more "spin-orbit coupling" you get, so by the time you are in period 7 or 8, it's a bit dubious to think of individual 5g orbitals anyways: those individual n, m, l, s quantum numbers don't describe electrons well anymore, cos they don't include spin-orbit coupling.--feline1 15:31, 24 January 2006 (UTC)

Capitalisation

As far back as I can recall, the Periodic Table has always been referred to in the proper sense. It is, after all, the only such table (at least as far as current quantum theory and chemistry bears out). As such, it seems as though not capitalising "Periodic Table" is improper. Anyone else have comments? Chris Lawson 05:33, 24 Jan 2005 (UTC)

Uhh.. Not a good source for wikipedia.

I was just about to use this table to explain how impurities relate with valence electrons. You don't give the valence electron order here and that's not cool. Nor does wikipedia talk about trivalents as of current as so I have to explain the whole thing from scratch. Throw the periodic chart and get permission from someone to use theirs. Or else make it more detailed. Or better yet pressure wikipedia into allowing macromedia flash files with a maxium upload size. --Cyberman 03:06, 10 Feb 2005 (UTC)

We do have a table with electron configurations, if that is what you want. And the solution to having incomplete information is definately not deleting what we have and starting over. Eric119 03:50, 10 Feb 2005 (UTC)

atomic mass

On the individual pages for the elements, in the table it says 'atomic weight', surely this is wrong, i have always heard it called 'atomic mass'. Weight is only in the presence of gravity? and from the weight page "Although terms such as "atomic weight", "molecular weight", and "formula weight" may still be encountered, such usage is often discouraged; terms like atomic mass are used instead."

I think this should be changed. thanks Bluemoose 16:27, 28 Mar 2005 (UTC)

periodic table changes

I just reverted periodic table changes by an anon. The changes talked about dotted and dashed lines although there were the same and the language wiki links were messed up in the same edit. Can anyone check this? - Tεxτurε 15:32, 18 May 2005 (UTC)

As the person who started the categorization this way, I know what it was supposed to do. On most periodic tables there are what is called "synthetic elements" some of which are naturally occuring and some of which that are actually synthetic are not listed as such. I have already stated why plutonium is listed as natually occuring and primordial plutonium has been isolated. Even though there are about a total of 6 grams on the entire planet earth. However, the editor marked califorium as a natural decay element, this is patently wrong. No element is naturally formed that is that atomically heavy. The element name that was changed also has no IUPAC sanction and hence by convention not used (AFAIK). The editor also changed other version of the period table.--metta, The Sunborn 17:37, 18 May 2005 (UTC)