What are isotopes? With reference to which fundamental particle do isotopes differ ? Give two uses of isotopes.

Isotopes are atoms of the same element having same atomic number but different mass number.

For example : ²⁴₁₂Mg and ²⁶₁₂Mg

Isotopes differ in the number of neutrons.

Uses of isotopes

1. Radioactive isotopes are used in industry to detect the leakage in underground oil pipelines, gas pipelines and water pipelines.
2. An isotope of Uranium ²³⁵₉₂U is used as a fuel in nuclear reactors.