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

[Rick Tarara <rtarara@saintmarys.edu>]

As you pursue Bernard's suggestion, note that the two ODD proton elements on 
either side of Tc (Nb and Rh) each have only a single stable isotope.  This 
is also true for Z = 59 Pr, but not for Z = 63 Eu (although it has only 2 
stable isotopes).  The higher mass rare earths also tend to have high 
nuclear deformations--to the point where one can often identify a series of 
low lying energy states that correspond to simple dumbell rotational states.

Rick

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Saint Mary's College
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rtarara@saintmarys.edu
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----- Original Message ----- 
From: "Bernard Cleyet" <bernardcleyet@redshift.com>


> Check for the even/oddness of the nucleons and look into magic numbers
> -- remember the nucleus is a bit like the atom in this way.
>
> bc, writes off the top of his head.
>
> Eric Scerri wrote:
>
> > I would be interested to learn why these two elements are radioactive
> > even though they have relatively low atomic numbers.
> >
> > This is true of Tc especially, for which Z = 43.
> > For Pm Z = 61.
> >
> > Subsequent elements are not radioactive until one reaches Po (Z =84)
> > and all subsequent elements.
> > What is special about Tc and Pm ?
> >
> >
> >
> > regards,
> > eric scerri
> >
> >
> > P.S.  I cover basic nuclear physics and nucleosynthesis in the final
> > chapter of my new book but was not able to answer this nagging question.
> >
> >
> > ------------------------------------------------------------------------ 
> > ------------------------------------------------------------------------ 
> > -------------
> > The Periodic Table: Its Story and Its Significance, by Eric Scerri,
> > Oxford University Press, 2007.
> >
> >        "An absolutely gorgeous book.  I put it on my bedside table
> > and then stayed up half the night reading it - it is immensely
> > readable."
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> > for a Hat, Awakenings etc.
> > ------------------------------------------------------------------------ 
> > ------------------------------------------------------------------------ 
> > ---------------------------------------------
> >
> > Dr. Eric Scerri
> > Department of Chemistry & Biochemistry,
> > Charles Young Drive,
> > Los Angeles,
> > CA 90095-1569.
> >
> > 310 206 7443
> > fax: 310 206 2061
> >
> > UCLA faculty web page:   http://www.chem.ucla.edu/dept/Faculty/scerri/
> >
> > Editor of Foundations of Chemistry,
> > http://www.springer.com/sgw/cda/frontpage/0,11855,4-40399-70-35545882-
> > detailsPage%253Djournal%257CmostViewedArticles%257CmostViewedArticles,
> > 00.html
> >
> > International Society for the Philosophy of Chemistry,
> > http://ispc.sas.upenn.edu/
> >
> >
> >
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