Question

short note on isotope​

Answer 1

Answer:

same atomic number but different mass number

Answer 2

Isotopes are variants of a particular chemical element which differ in neutron number, and consequently in nucleon number. ... The number of nucleons (both protons and neutrons) in the nucleus is the atom's mass number, and each isotope of a given element has a different mass number.

or

Isotopes are elements which have same atomic number but different atomic masses