Chapter 1, Problem 18PP

Interpretation Introduction

Interpretation: Resonance structures for the formate ion, ${\text{HCO}}_2^{-}$, are to be drawn. Also, the prediction of the carbon-oxygen bond lengths and the electric charge on the oxygen atoms need to be explained.

Concept Introduction:

Resonating structures are structures that have more than one equivalent Lewis structure for the same molecule or ion.

Resonance structures have existence in paper only, thus, they are not real structures.

According to the convention, these structures are connected by double-headed arrows ($\stackrel{}{\leftrightarrow }$)

The movement of electrons is represented by curved arrows.

The energy of any contributing structure is higher than the energy of the resonance hybrid.

For equivalent resonating structures, the resonance stabilization is large.