ACS Chemistry Practice Exam 2025 – The All-in-One Guide to Exam Success!

The true structure of a molecule involving resonance is represented by a resonance hybrid, which is essentially an average of all the valid resonance structures. Resonance structures are theoretical constructs used to illustrate the delocalization of electrons across certain bonds or atoms in a molecule. Each individual resonance structure contributes to the overall description and properties of the molecule, but none of them can fully capture the actual electronic distribution.

This averaging effect implies that the resonance hybrid is more stable than any single resonance contributor because it takes advantage of the stabilizing effects of electron delocalization. Therefore, while some resonance structures may represent more stable arrangements (usually being lower in energy), the actual molecule exists as a blend of these forms rather than as any one of them alone. The idea that the resonance hybrid is an average highlights the importance of all contributing structures in determining the overall properties of the molecule.