What is the term for a negatively charged ion?

The term for a negatively charged ion is "anion." This designation arises from the way ions are formed and classified based on their electrical charge. Atoms can gain or lose electrons to form ions: when an atom gains one or more electrons, it acquires a negative charge because electrons carry a negative charge. As a result, the atom becomes an anion.

In contrast, cations are positively charged ions formed when an atom loses electrons. Neutral ions would imply a balance of protons and electrons, resulting in no overall charge. Isotopes refer to variations of a particular element that have the same number of protons but different numbers of neutrons, which does not relate directly to charge. Therefore, the correct understanding of a negatively charged ion is anchored in the concept of anions and their properties.