In chemistry, resonance is a method of comparing and contrasting two or more different Lewis dot structures that can possibly represent a molecule. It illustrates the delocalization of electrons within molecules. Delocalization is the movement of electrons, which helps stabilize the molecule.
When one Lewis structure is unable to describe completely the bonding that takes place between atoms in a molecule, resonance structures are used. A resonance hybrid is the net sum of all valid Lewis structures for the molecule. Molecules with several resonance structures are more stable than molecules with fewer resonance structures. The skeleton of the structure remains the same in resonance structures, as do the pairs of lone electrons.