Talk:Promethium

Template:Chemical Element Article changed over to new Wikipedia:WikiProject Elements format by schnee. Elementbox converted 11:09, 10 July 2005 by Femto (previous revision was that of 13:31, 9 July 2005).

Information Sources

Some of the text in this entry was rewritten from Los Alamos National Laboratory - Promethium. Data for the table was obtained from the sources listed on the subject page and Wikipedia:WikiProject Elements but was reformatted and converted into SI units.

Similarly, does it occur naturally or not? Current article says "Promethium does not naturally occur on Earth" (in Occurence section), but also mentions that "promethium is still recovered from the byproducts of uranium fission." Since uranium undergoes spontaneous fission, does it follow that promethium is produced spontanously as a product of uranium? Jeneralist 22:07, 10 September 2006 (UTC)[reply]

Yes. It's a tiny amount because only a tiny fraction of the uranium atoms undergo spontaneous fission (as opposed to alpha decay), and only a tiny fraction of those fission events form relatively long-lived isotopes of promethium, but it is produced spontaneously that way. —Keenan Pepper 22:37, 10 September 2006 (UTC)[reply]

Found a reference in the literature to that effect and updated the "Occurence" section accordingly. Jeneralist 04:59, 17 September 2006 (UTC)[reply]

Isotopes

What does this mean?

The isotopes of promethium range in atomic weight from 127.9482600 u (128Pm) to 162.9535200 u (163Pm).

I thought isotopes were in whole numbers and a fractional designation represented a mix of isotopes?

An isotope is represented by whole number (total number of neutrons and protons), but the atomic mass of a specific isotope is not due to nuclear binding energy. DMacks 19:08, 10 October 2006 (UTC)[reply]

So where this Promethium page says "Promethium's longest lived isotope (atomic weight 145 u)", should that parenthesis really be (mass number 145) ? The actual atomic weight of Pm-145 is 144.912 u or thereabouts. Fathead99 08:12, 10 May 2007 (UTC)[reply]

Rewritten. Femto 14:19, 10 May 2007 (UTC)[reply]

Why is it radioactive?

Why are the elements technetium and promethium radioactive? It is because they are syntheticized? They seem like just two random spots on the periodic table that have no stable isotopes. They are usually artficial, but they can be both found naturally on Earth and in Space. They don't emmit alpha particles, but they do emit beta particles, and some emit gamma particles. Beta particles usually indicate that the isotope has too many or not enough neutrons. However, almost all elements have radioactive isotopes, but these two don't have any stable isotopes. Is there any particular reason why these elements have no known existing isotopes that are non-radioactive, besides the fact that they are usually syntheticated? AstroHurricane001 13:32, 5 December 2006 (UTC)[reply]

Just a nit to pick, but all elements have radioactive isotopes. Not all are found naturally, though. Jokem 04:55, 23 June 2007 (UTC)[reply]

Since we're nitpicking, is it not true that no isotope is truly stable (with the conceivable exception of Fe), but rather "stable" is a completely arbitrary line across the continuous domain of long half-lives? 150.203.48.127 (talk) 01:37, 8 April 2008 (UTC)[reply]

I am not enough of a Nuclear Physicist to talk about this, maybe someone else here can comment? My understanding is an isotope is stable if it does not spontaneously emit. Jokem (talk) 19:15, 15 April 2008 (UTC)[reply]

I know I'm a year late, but just to let you know, Tc and Pm are not stable because the valley of beta stability lies in an area where both elements around it (Mo and Ru; Nd and Sm) have stable isotopes for each mass number. So Tc and Pm will always undergo beta decay, as they can't find stable configurations. --121.7.203.206 (talk) 06:39, 22 May 2009 (UTC)[reply]

semi-stable isotope

OK, what is a semi-stable isotope? —The preceding unsigned comment was added by 12.41.204.3 (talk) 22:32, 5 December 2006 (UTC).[reply]

I would think it's an isotope of a particular element that is still radioactive, but is relatively stable (has a long half-life) compared to other radioactive isotopes. You might find more answers on other pages. AstroHurricane001 22:53, 5 December 2006 (UTC)[reply]