Radioactive Decays

Abstract

Decays are a category of reaction where a particle, or a nucleus, transforms into two or more particles or nuclei. We have already introduced the α −, β- and γ-emitting decays. In the α decay (Fig. 4.1), the parent nucleus emits an α particle, which is a nucleus of $^4_2{\mathrm {He}}$, and the resulting daughter nucleus has an atomic number which is two units lower and a mass number which is four units lower. In the β decay (Fig. 4.2), an electron or a positron is emitted, and the resulting daughter nucleus has an atomic number lower by one unit, while the mass number remains unchanged (Table 4.1).