What type of ion is formed when non-metals gain electrons?

When non-metals gain electrons, they form anions. This process occurs because non-metals typically have high electronegativities and a tendency to accept electrons to achieve a stable electron configuration, often resembling that of the nearest noble gas. By gaining one or more electrons, a non-metal atom becomes negatively charged, as the additional electrons outnumber the positive protons in the nucleus. This negatively charged ion is termed an anion.

For instance, when a chlorine atom gains an electron, it becomes a chloride ion (Cl⁻). The formation of anions is a key concept in understanding chemical bonding and reactions, particularly in ionic compounds, where these negatively charged ions pair with positively charged cations (which are formed when metals lose electrons). Understanding this behavior is fundamental to grasping the nature of chemical interactions in various substances.