What is the process by which an atom loses or gains electrons?

The process by which an atom loses or gains electrons is known as ionization. When an atom loses one or more electrons, it becomes a positively charged ion, called a cation. Conversely, when an atom gains electrons, it becomes a negatively charged ion, known as an anion. This fundamental change in charge due to the alteration of electron count is central to many chemical reactions and interactions, particularly in the fields of chemistry and physics.

While other terminology such as oxidation and reduction is related to electron transfer, they refer specifically to the loss (oxidation) or gain (reduction) of electrons in a chemical reaction context. Electrification, on the other hand, typically describes a broader concept of charging objects, which may involve the transfer of electrons but is not limited to atomic interactions. Hence, ionization is the most accurate term for the process of directly losing or gaining electrons at the atomic level.