Question

why nuclei have mass less than the sum of the masses of the individual nucleons in them??​

Answer 1

❤Hola ❤

when nucleons are brought to form a nucleus a fraction of their mass is converted into the energy to hold this nucleons in the nucleus hence mass of A nucleus is less than the sum of individual nucleons in them .

Answer 2

So mass of the nucleus found is less than the sum of the masses of the individual nucleons. Since proton number and neutron number areconserved in a nuclear reaction, the total rest mass of neutrons and protons is the same on either side of a reaction.