Step-by-step explanation:
It is known that protons and neutrons reside inside the nucleus of an atom. Protons are positively charges and neutrons have no charge.
So, due to like charges of protons there occurs an electrostatic force of repulsion but this force of repulsion is overcome by nuclear binding energy. Due to nuclear binding energy both protons and neutrons remain inside the nucleus of the atom.
This binding energy is also known as strong nuclear force which keeps the stability of nucleus.
But when there is large difference in the number of protons and neutrons then there will repulsive forces overcome binding energy. Therefore, in that case atom becomes unstable as weak nuclear force is acting inside the nucleus. Hence, unstable atom will undergo radioactive decay.
Therefore, we can conclude that radioactive decay is most likely to happen to an atom when there are imbalances between its strong and weak nuclear force.