Which of the following are the characteristics of isotopes of an element?

(i) Isotopes of an element have same atomic masses.

(ii) Isotopes of an element have same atomic number.

(iii) Isotopes of an element show same physical properties.

(iv) Isotopes of an element show same chemical properties.

Isotopes are two or more forms of an element in which the atoms have the same number of protons. Also different isotopes of an element have different mass numbers, hence the number of neutrons in the nuclei of isotopes of an element are different. All isotopes have similar chemical properties.

For example, hydrogen (H) has three isotopes having mass numbers 1, 2 and 3, but all having atomic number equal to 1.