Any form of a chemical element, which has the name number of protons or the same atomic number, but has a difference in the number of neutrons in the nucleus, is called an isotope.
This change in the number of neutrons also differs in their relative atomic mass.
But the chemical properties do not change.
Some examples are isotopes of hydrogen are deuterium, and tritium .
Uses of isotopes:-
Isotopes of Uranium (Uranium) are used as fuels in a nuclear reactor.
Isotopes of Is Iodine(Iodine-) are used in the treatment of goitre.
Isotopes of Cobalt (Cobalt) are used in cancer treatment.