Question

Correct expression for mass defect Δm is ______.

Options

• Zm_p - (A - Z)m_n - M

• Zm_p + (A - Z)m_n - M

• Zm_p - (A - Z)m_n + M

• Zm_p + (A - Z)m_n + M

Answer 1

Correct expression for mass defect Δm is Zm_p + (A - Z)m_n - M.

Explanation:

The mass of an atom is always slightly less than the total of the masses of the individual neutrons, protons, and electrons that make up the atom, according to measurements. The mass defect is the difference between the mass of an atom and the sum of its constituents' masses.

The number of protons (atomic number) is Z, and the number of neutrons is (A - Z), with A denoting the total number of nucleons (mass number) and M denoting nuclear mass.