radioactive decay definition geology
radioactive decay-the spontaneous disintegration of a radioactive substance along with the emission of ionizing radiation. disintegration, decay. alpha decay-radioactive decay of an atomic nucleus that is accompanied by the emission of an alpha particle. beta decay-radioactive decay of an atomic nucleus that is accompanied by the emission of a beta particle. nuclear reaction - (physics) a process that alters the energy or structure or composition of atomic nuclei. 1  Facebook.