In nuclear reaction there's often a measurable diff on mass and not the result of errorin massingWhat's reason

Question

In nuclear reaction there is often a measurable difference in the masss of the reactants and the mass of products that is not the result of error in massing.What is the reason for the differences in mass Value?

Answer 1

As Einstein would put it, "e = mc^2" The energy difference is the binding energy per necleon in the nucleus. In each nuclear reaction, the daughter nucleus is born in an excited state. This is because of the difference in mass between the nucleons of the decaying nucleus and that of the daughter. It relaxes at once to a ground state by emission of gamma rays.