Final answer:
An anion is a negatively charged ion, while a cation is a positively charged ion. Anions are formed when atoms gain electrons, while cations are formed when atoms lose electrons.
Step-by-step explanation:
An anion is a negatively charged ion, while a cation is a positively charged ion. Anions are formed when a neutral atom gains one or more electrons, while cations are formed when a neutral atom loses one or more electrons. In the preceding example, the anion would be the ion that has a net negative charge.