Answer:
False: Isotopes have variable number of Neutrons.
Step-by-step explanation:
Isotopes are defined as those atoms of same element which have same number of protons but different number of neutrons hence, isotopes have different number of neutrons and mass number respectively.
Example:
Hydrogen have three Isotopes;
i) Protium-1 having 0 neutrons
ii) Deuterium-2 having 1 neutron
iii) Tritium-3 having 2 neutrons
While, when the number of electrons for a particular atom varies it results in the formation of ions of that atom.
Example:
Hydrogen when looses one electron it converts into H⁺
Nitrogen when gains three electrons it converts into N⁻³
Chlorine when gains one electrons it converts into Cl⁻
Magnesium when looses two electrons it converts into Mg⁺⁺