In isotopes does anything happen to the electron number. Explain.

No! Isotopes are defined as the variant of any element that has equal number of protons and electrons but a different number of neutrons in the nucleus.

Explanation:

The term "Isotope" is coined by the Greek words iso (means same) and topos (means place) colloquially termed as the variants of element that stays in the same place in the periodic table.

Thus isotopes don't have different number of electrons but when they are in the neutral state. For example, Carbon-12, 13 and 14 are the three isotopes, having different mass number because of different number of neutrons in their nuclei.