Ion

Definition

An ion is an atom or molecule that has gained or lost one or more electrons, resulting in a net electric charge. Ions can be either positively charged (cations) or negatively charged (anions).

5 Must Know Facts For Your Next Test

1. Ions are formed when atoms gain or lose electrons to achieve a more stable electron configuration.
2. Cations are positively charged ions formed by the loss of electrons.
3. Anions are negatively charged ions formed by the gain of electrons.
4. Ions play crucial roles in chemical reactions, especially in the formation of ionic bonds.
5. The charge of an ion is indicated by a superscript number and sign (e.g., Na$^+$, Cl$^-$).

Review Questions

• What is the difference between a cation and an anion?
• How does an atom become a cation?
• Why do ions form during chemical reactions?

Related terms

Cation:

A positively charged ion that forms when an atom loses one or more electrons.

Anion: A negatively charged ion that forms when an atom gains one or more electrons.

Ionic Bond: A type of chemical bond formed through the electrostatic attraction between oppositely charged ions.