a radioactive process in which an alpha particle is emitted from the nucleus of an atom, decreasing its atomic number by two.
Origin of alpha decay
First recorded in 1935–40
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
the radioactive decay process resulting in emission of alpha particles
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
The radioactive decay of an atomic nucleus by emission of an alpha particle (two protons bound to two neutrons). When an element undergoes alpha decay, its atomic number decreases by two.
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