Question

How do you know if a compound has Resonance ?

Answer 1

1. Owing to the overlap of orbitals, resonance exists. Double bonds, formed from the overlap of $2\mathrm{p}$ orbitals, are composed of $\mathrm{\pi }$ bonds. In these $\mathrm{\pi }$ orbitals, the electrons would be scattered over more than two atoms, and are thus delocalized.
2. The increase in stability is called the strength of resonance.
3. The notion of resonance effect tells of the polarity caused by the reaction between a lone electron pair and a $\mathrm{\pi }$ bond in a molecule. It also happens in the neighboring atoms via the interaction of $2\mathrm{\pi }$ bonds. Resonance helps to consider the stability of a substance along with the energy states in chemistry.
4. The below diagram shows the resonance structure of ${\mathrm{CO}}_3^{-2}$