![[alphaDecay.png|align:center|300]] $\ce{^{A}_{Z}X} \longrightarrow \ce{^{(A-2)}_{(Z-2)}X} + \ce{^{4}_{2}He}$ Alpha decay is the nuclear decay process whereby a parent nucleus emits an alpha particle ($\alpha$). > [!reminder] Alpha Particle > An alpha particle ($\alpha$) is the equivalent of a helium-4 nucleus ($\ce{^{4}_{2}He^{+2}} \equiv \ce{^{4}He}$), composed of 2 protons ($p$) and 2 neutrons ($n$).