PCC Chemistry Competency Practice Exam

An ion with a negative charge is called an anion. Ions form when atoms gain or lose electrons: gaining electrons adds negative charge, so the resulting ion becomes negative (an anion). The opposite is a cation, which is a positively charged ion formed when an atom loses electrons. An ionic compound is a substance made of both cations and anions held together, not a single ion. A physical property is a characteristic of matter, not a type of ion. So the term for a negatively charged ion is an anion, with common examples like chloride ion or oxide ion.