Re: [Phys-l] question on radioactivity of Tc and Pm

[Rick Tarara <rtarara@saintmarys.edu>]

The periodic table does a bang-up job describing the chemical properties of 
the elements, but when you get to the nuclear properties, it gets more 
complicated.  (Now I'm trying to draw on 30 year old background...but)  You 
have the equivalent of a shell model with the nucleons, you have the strong 
nuclear force with is very much a function of separation, your have to worry 
about spin and angular momentum properties, about the nucleus becoming 
oblong rather than spherical, other quantum effects like isotopic spin, etc. 
While nothing dramatic may point to Tc and Pm being unusual at the atomic 
level, they clearly are at the nuclear level.  From the info I sent earlier 
it is pretty clear that the odd Z nuclei either side of these two are less 
stable than other nuclei in their regions where there are often several 
stable isotopes.  So, something is going on the the nuclear structure with 
these elements being at a cusp of stability.  I would think a little more 
research (I'm well behind today already) should reveal what that is.

Rick

----- Original Message ----- 
From: "Eric Scerri" <scerri@chem.ucla.edu>
> Or am I merely a poor deluded chemist wanting to see matters in terms
> of elements characterized by Z values rather than treating isotopes
> as the basic units?
> Incidentally there is a whole story to tell on this point, some of
> which I recount in the book which is mainly an examination of the
> extent to which physics does or does not explain the periodic table.
>
> regards,
> eric scerri