What term is used for atoms that have gained or lost electrons?

Atoms that have gained or lost electrons are referred to as ions. When an atom loses one or more electrons, it has fewer negatively charged electrons than positively charged protons, resulting in a positive charge; this type of ion is known as a cation. Conversely, when an atom gains electrons, it has more electrons than protons, resulting in a negative charge, which is known as an anion. The ability of atoms to gain or lose electrons is crucial in chemical reactions and plays a significant role in electrical conductivity, such as in marine environments where corrosion can occur through electrochemical processes.

Other terms like isotopes, molecules, and protons do not accurately describe the process of gaining or losing electrons. Isotopes refer to variations of the same element that have different numbers of neutrons, while molecules are groups of atoms bonded together. Protons are positively charged particles found within the nucleus of an atom and do not refer to any process involving the gain or loss of electrons. Hence, ions is the correct terminology for this concept.