Question

what is the main cause for existence of isotopes?

Answer 1

The number of electrons present inside an atom or element determines the chemical properties of the atom or element. Because the number of electrons in an atom and its isotopes are the same, the chemical properties of an isotope are similar to that of the parent atom. On the other hand, heavy isotopes have large masses and different chemical properties as compared to their parent atoms. This phenomenon is termed as Kinetic Isotope Effect.