Chapter 1, Problem 1.19P

Interpretation Introduction

Interpretation:

Out of the two shown structures, the resonance structure that makes a greater contribution to the resonance hybrid is to be determined.

Concept introduction:

Resonance structures are alternate Lewis structures that can be drawn for a molecule. All the resonance structures do not contribute equally to the resonance hybrid. The structure with the lowest energy contributes the most. A greater number of atoms (other than hydrogen) with an octet of electrons and a greater number of covalent bonds results in a lower energy structure. A lower number of atoms with formal charges also leads to a lower energy structure.

Formal charge (FC) on an atom is calculated as

$\text{FC = Group number - (Number of lone pair electrons + }\frac{1}{2}\times \text{number of bond electrons)}$