Answer: Option (B) is the correct answer.
Explanation:
Isotopes are the substances or species that contain same number of protons but different number of neutrons.
As it is known that atomic number means the total number of protons present in an atom. Hence, this also means that in isotopes atomic number of the species is same.
For example, isotopes of hydrogen are [tex]^{1}_{1}H[/tex], [tex]^{2}_{1}H[/tex], and [tex]^{3}_{1}H[/tex].
Isotopes of only heavier elements are radioactive in nature as they have large difference in the number of protons and neutrons.
Thus, we can conclude that the statement isotopes of the same element have the same atomic number but differ in their atomic masses, is correct.
