Electron Capture

${}_{}^{}{}_{\mathrm{Z}}^{\mathrm{A}}\mathrm{X}+{}_{}^{}{}_{-1}^0\mathrm{e}\to {}_{}^{}{}_{\mathrm{Z}-1}^{\mathrm{A}}\mathrm{Y}$

• An atom captures an electron, converting a proton into a neutron