What are electrically charged atoms called?

Electrically charged atoms are called ions. An atom becomes an ion when it gains or loses one or more electrons, upsetting the balance between its positively charged protons and negatively charged electrons.

An atom that loses electrons becomes a positively charged cation; one that gains electrons becomes a negatively charged anion. Sodium ions (Na+) and chloride ions (Cl-) are familiar examples, and their attraction forms ordinary table salt.

The term ion was introduced by Michael Faraday in 1834 while describing charged species moving through solutions during electrolysis. Although the original question says “atoms,” ions can also be molecules made of several atoms, such as sulfate (SO4²−) or ammonium (NH4+).

A related term is ionization, which means the process of creating an ion. Ions are essential in nerve signals, batteries, mineral-rich water, chemical reactions, and the electrical conductivity of salt solutions.