Question

For greater stability, a nucleus should have greater value of binding energy per nucleon. Why?

Answer 1

Binding energy is the energy that holds a nucleus together and is equal to the mass defect of the nucleus. For stable nucleus, we can see that native prefers even number of protons and an even number of neutrons. The odd combination of protons and neutrons in the nucleus are very less and are only found in lighter elements. For elements with large number of protons in the nucleus, the coulomb electrostatic force of repulsion becomes significant and the number of neutrons must be greater to compensate this repulsion effect.

Therefore the basic point is that the binding energy of a nucleon is directly proportional to the stability of the nucleus,. Since stability is what determines whether the nucleus will decay, which ultimately is affected by the binding energy.