Level: introductory
Reference: Frederick Soddy, "The Radio-elements and the Periodic Law," Chemical News 107, 97-9 (1913)
Notes: Frederick Soddy (1877-1956) is remembered for three major contributions toward the understanding of radioactivity and associated phenomena. With Ernest Rutherford, he saw that radioactive substances were transformed from one element to another. (Rutherford is supposed to have urged his colleague, "Don't call it transmutation. They'll have our heads off as alchemists."[1]) About 10 years later, he unravelled the rules for the elemental transformations which accompanied radioactive decay, first for α decay and later for β decay. Emission of an α particle changes the emitting atom to an atom of the element two places to the left in the periodic table; emission of a β particle changes the emitting atom to an atom of the element one place to the right. These rules taken together are known as the radioactive displacement Law; Kasimir Fajans published it slightly earlier than did Soddy. At about the same time, Soddy came to the conclusion that several substances with different radioactive properties and different atomic weights were chemically the same element. He named such substances isotopes. Soddy received the Nobel Prize for chemistry in 1921 for his work on isotopes.
Solutions: To download solutions, go to:
http://web.lemoyne.edu/giunta/classicalcs/soddy.doc
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