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CHEM 121 Studioby Learn4Less · UBC CHEM 121

CHEM 121 glossary

Ionic bond

The electrostatic attraction between oppositely charged ions, formed when one atom transfers electrons essentially completely to another. This course calls a bond ionic when ΔEN≥1.8\Delta\text{EN} \geq 1.8.

Ionic solidA regular lattice in which small cations (+) and larger anions (−) alternate, as in sodium chloride. Every ion is held by strong attractions to all its oppositely charged neighbours; there are no separate molecules.+−+−+−−+−+−++−+−+−−+−+−+cations (+) and anions (−) alternate, e.g. Na⁺Cl⁻high melting, brittle; conducts when molten

Each ion is attracted to all its oppositely charged neighbours, not to one partner.

Example

K–F: ΔEN=3.98−0.82=3.16\Delta\text{EN} = 3.98 - 0.82 = 3.16, so KF is ionic: KX+\ce{K+} and FX−\ce{F-} ions held in a lattice.

See alsoElectronegativityCovalent bondPolar covalent bondElectronegativity difference (ΔEN)