Which of the following describes an anion?

An anion is defined as a negatively charged ion, which means it has gained one or more electrons resulting in an overall negative charge. When an atom or molecule gains electrons, its number of protons (which determines its positive charge) remains the same, leading to a net negative charge. This characteristic distinguishes anions from cations, which are positively charged ions formed by the loss of electrons. Therefore, identifying an anion correctly as a negatively charged ion captures the critical aspect of its nature in the context of electron transfer and charge balance in chemical reactions.