An isotope is any variant of a chemical element that has the same number of protons but a different number of neutrons. → Example: Carbon-12 and Carbon-14 are both isotopes of carbon.

A radioactive isotope (also called a radioisotope) is a special kind of isotope that is unstable and decays over time, emitting radiation (like alpha, beta, or gamma rays).

In short: 👉 All radioactive isotopes are isotopes, But not all isotopes are radioactive.