What is the primary difference between an isotope and an ion?

The primary difference between an isotope and an ion lies in their definitions regarding atomic structure. Isotopes of an element have the same number of protons, which defines the element, but differ in the number of neutrons. This variation in neutrons results in different atomic masses for the isotopes, while the chemical properties remain largely the same because they have the same number of protons (and therefore the same electron configuration).

An ion, on the other hand, is defined by the imbalance between the number of protons and electrons. When an atom loses or gains electrons, it becomes charged — positively, if it loses electrons, or negatively, if it gains them. This charge distinguishes the ion from a neutral atom, which has an equal number of protons and electrons.

Understanding these distinctions is crucial in chemistry, as isotopes are often used in applications like radiometric dating and nuclear medicine, while ions are fundamental in understanding chemical bonding and reactions due to their charged nature.