Chapter 6, Problem 43QRT

Write the correct Lewis structure and assign a formal charge to each atom in fulminate ion, CNO⁻.

Interpretation Introduction

Interpretation:

The correct Lewis structure of fulminate ion ${\text{(CNO}}^{\text{-}}\text{)}$ and a formal charge of each atom have to be written.

Concept Introduction:

Lewis structure otherwise known as Lewis dot diagrams or electron dot structures. The bond between atoms and lone pairs of electrons that is present in the molecule.  Lewis structure represents each atom and their position in structure using the chemical symbol.  Excess electrons forms the lone pair are given by pair of dots, and are located next to the atom.

The formula for the formal charge can be written as

  $\text{Formal}\text{charge=}\text{Valence}\text{electrons-lone}\text{pair}\text{electrons}\text{-}\frac{\text{Bonding}\text{electrons}}{\text{2}}$

Explanation of Solution

The correct Lewis structure of the fulminate ion ${\text{(CNO}}^{\text{-}}\text{)}$ can be drawn as,

Achart can be drawn as,

  $\overline{\begin{array}{l}\text{C}\text{N}\text{O}\\ \text{I}\text{II}\text{III}\text{I}\text{II}\text{III}\text{I}\text{II}\text{III}\\ \overline{\underset{\_}{\begin{array}{l}\text{Valence}\text{electrons}\text{4}\text{4}\text{4}\text{5}\text{5}\text{5}\text{6}\text{6}\text{6}\\ \text{Lone}\text{pair}\text{electrons}\text{2}\text{4}\text{6}\text{0}\text{0}\text{0}\text{6}\text{4}\text{2}\\ \text{Bonding}\text{electrons}\text{6}\text{4}\text{2}\text{8}\text{8}\text{8}\text{2}\text{4}\text{6}\\ \text{Formal}\text{charge}\text{-1}\text{-2}\text{-3}\text{+1}\text{+1}\text{+1}\text{-1}\text{0}\text{+1}\end{array}}}\end{array}}$

The total number of valence electron is $16.$  the central Nitrogen atom wants to two multiple bond.

The Fulminate ion ${\text{(CNO}}^{\text{-}}\text{)}$ has three resonance structures, the best Lewis structure (I) because the lowest number formal charge structure.