Nuclides for which $\frac{N}{Z}$ is too small for stability can emit a positron, the electron's antiparticle which is identical to the electron, but with positive charge. The basic process called ${\mathrm{\beta }}^{+}$ decay.

${}_Z{}^{A}X \to {}_{Z-1}{}^{A}Y+ e^{+}+\gamma $ $$

($\gamma =$neutrino$)$