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Definition of Alpha Decay


Definition: Alpha decay is the spontaneous radioactive decay where an alpha particle is produced.

An atom that undergoes alpha decay will reduce its atomic mass by 4 and become the element two atomic numbers less. The general reaction for alpha decay is

ZXAZ-4YA-2 + 4He2

where X is the parent atom, Y is the daughter atom, Z is the atomic mass of X, A is the atomic number of X.

Examples: 238U92 decays by alpha decay into 234Th90.

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