When a nucleus in an atom undergoes a radioactive decay, the electronic energy levels of the atom.

For  $\mathrm{\alpha }\mathrm{and}\mathrm{\beta }-$radioactivity electronic energy levels changes. An alpha particle carries 2 units of positive charge, and a beta particle carries one unit of negative charge and γ (particle) carries no charge. Alpha and beta decay eject charged particles from the nucleus, altering its charge and its interactions with electrons, which in turn alter the electronic energy levels.