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.