Glossary
ionic bond
An ionic bond forms when a metal transfers electrons to a nonmetal and the two opposite ions attract.
An ionic bond is the attraction between oppositely charged ions, formed when a metal gives electrons away and a nonmetal takes them. A metal has few valence electrons and loses them easily, becoming a positive ion; a nonmetal needs a few and gains them, becoming negative. The two opposite charges then attract and hold the compound together. The charges must balance, so you predict the formula from the ions: Mg²⁺ with Cl⁻ needs two chlorides, giving MgCl₂. Ionic compounds have high melting points, because the attractions are strong, and they conduct electricity when dissolved in water or melted, because the ions are then free to move. The common mix-up is to call a metal-plus-nonmetal pair covalent; a transfer makes ions (ionic), while sharing makes molecules (covalent).
Taught in
Related terms
- ion — An ion is an atom (or group) with a charge, made by losing or gaining electrons; a metal loses, a nonmetal gains.
- covalent bond — A covalent bond forms when two nonmetals share pairs of electrons rather than transferring them.
- valence electron — Valence electrons are the electrons in an atom's outermost shell; they decide bonding and the element's group.
Source: OpenStax Chemistry 1e and Chemistry: Atoms First 1e, first editions (CC BY 4.0). Each definition restates the Chemistry guide in this exam, which carries the per-source citations on its own page. (OpenStax 1e accessed 2026-10-08)