Chapter 9, Problem 9.48QP

Interpretation Introduction

Interpretation:

Two Lewis structures for formaldehyde labelled as ‘a’ and ‘b’ in example 9.7 of the text book.  Apart from the reason given in text book for choosing structure ‘b’ as plausible structure the other two reasons have to be written.

Concept Introduction:

Formal charge on an atom refers to the electrical charge difference between number of valence electrons of atom in isolated state and the number of electrons assigned to that atom in Lewis structure.

It is calculated by an equation,

${\text{formal charge = e}}_{\text{v}}{\text{-e}}_{\text{n}}\text{-}\frac{{\text{e}}_{\text{b}}}{\text{2}}$

Where,

$\begin{array}{l}{\text{e}}_{\text{v}}\text{= no}\text{.of valence electrons}\\ {\text{e}}_{\text{b}}\text{= no}\text{.of bonding electrons}\\ {\text{e}}_{\text{n}}\text{= no}\text{.of unshared}\text{electrons}\end{array}$

Molecules are electrically neutral species that the sum of the charges must be added up to zero.