Question

The number of protons in the nucleus is equal to:

Options

• The mass number A

• The atomic number Z

• The number of isotopes of the element

• The neutron number N

Answer 1

The number of protons in the nucleus equals the atomic number Z. Together with neutrons, protons make up the mass number through \[A = Z + N\], and the positive charge of the nucleus arises entirely from these protons.