When a negatively charged species is most appropriately depicted as a hybrid of several resonance forms, the negative charge present is considered to be rapidly moving between the resonance forms bearing the formal negative charge.True / False.

Resonance is a concept that was introduced when it was not possible to represent a compound with a single Lewis structure. Lewis formulas represent localized electrons, either shared by two atoms in a covalent bond or as non-shared electrons belonging to a given atom. Certain organic compounds, especially those containing multiple bonds can be described by more than one Lewis structure. In these cases, the true Lewis structure has an electronic distribution that is a "hybrid" of all possible Lewis structures of that molecule. Each of Lewis's structures is known as resonance or canonical forms and they are related to each other by a double-headed arrow, where all possible positions of electrons in that molecule are represented.

This type of compound has multiple bonds (double or triple) where electrons are not fixed, but move quickly between atoms, "resonating" between the different Lewis structures. For this reason, when a resonance hybrid has a negative charge, this charge moves between the different resonant structures.

Many times, an intermediate Lewis structure is drawn, with dotted lines, simulating approaching the real structure of the compound, and where this phenomenon of electron and charge mobility can be observed. For example, as we can observe in the ozone resonance image.