Answer: Some of the mass gets converted in the form of energy related to mass.
Explanation:
Mass defect is defined as the difference in the mass of an isotope and the mass number of an atom. Equation representing mass defect is:
[tex]\Delta m=[(n_p\times m_p)+(n_n\times m_n)]-M[/tex]
where,
[tex]\Delta m[/tex] = mass defect of an atom
[tex]n_p[/tex] = number of protons
[tex]m_p[/tex] = mass of one proton
[tex]n_n[/tex] = number of neutrons
[tex]m_n[/tex] = mass of one neutron
M = mass number
The mass number of an atom (mass of nucleus) is always less than the isotopic mass (total mass of its nucleons) because energy is released when nucleus gets formed. This energy is related to mass of the nucleus and is known as binding energy.
Hence, some of the mass gets converted in the form of energy related to mass.