Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
Resonance in chemistry refers to the phenomenon where a molecule or ion can be represented by two or more Lewis structures. These different structures, called resonance forms, contribute to the overall structure of the molecule.
A way that electrons can be arranged in a molecule or ion. Different resonance structures usually have the same arrangement of atoms but differ in electron placement.
Delocalized Electrons: Electrons that are spread over several adjacent atoms rather than being confined to one atom or pair of atoms. In molecules with resonance, these electrons are delocalized across all the atoms involved.
Conjugated System: A system in which atoms are linked by alternating single and double bonds, allowing for delocalization of electrons and thus enabling resonance.