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From: WC Maddox
As a starting point calculate the binding energy using the semi-empirical mass formula in Wikipedia.
End Message
At 12:25 AM 3/5/2007, you 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.
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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."
---Oliver Sacks, author of The Man Who Mistook his Wife
for a Hat, Awakenings etc.
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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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_______________________________________________
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