Assertion : Nuclear binding energy per nucleon is in the order - ₄^9 Be > ₃^7 Li > ₂^4 He . Reason : Binding energy per nucleon increases linearly with difference in number of neutrons and protons.

Step-by-step solution

Binding energy per nucleon of ₃ Li ^7(5.38 MeV ) is lesser than ₂ He ^4(7.08 MeV ) as helium is found to be more stable than Li. As the atomic mass number increases, the binding energy per nucleon decreases. As the atomic number and the atomic mass number increase, the repulsive electrostatic forces within the nucleus increase due to the greater number of protons in the heavy elements. To overcome this increased repulsion, the proportion of neutrons in the nucleus must increase to maintain stability. This increase