Chapter 8.3, Problem 42PP

Interpretation Introduction

Interpretation:

The Lewis dot structure of per chlorate ion, $Cl{O}_4^{(-)}$ using concepts of chemical bonding needs to be drawn.

Concept introduction:

For drawing Lewis structure one should know the formula of formal charge atom.

This is represented as follows:

Formal charge $=$ valence electrons $-$ non-bonding electrons/lone pair electrons $-$ bonding electrons $2.$

Explanation of Solution

Number of valence electron on $Cl\to 7\left(chlorine\right)$

Number of valence electron on $O\to 6\left(oxygen\right)$

Total number of valence electron on $Cl{O}_4^{(-)}\to 7+4\left(6\right)+1=32$ electrons.

Now, Cl forms double bond with 3 O atoms which results in zero lone pair of Cl and 2 lome pairs on each O atoms. It forms one single bond with 1 oxygen atom which results in the formation of negative charge on it. This is in conjugation with all the oxygen atoms. Also, the O atom with negative charge has 3 lone pair of electrons. Thus, the structure is represented as follows:

Now octet is satisfied for each atom but one has to adjust the formal charge.

Formal charge of chlorine $=7-0-\frac{8}{2}=3$

Formal charge of all $3$ oxygen atoms $=6-6-\frac{2}{2}=-1$

Lone pair on chlorine $=0$

Bonding electron for chlorine $=8$

Lone pair on oxygen $=3$

Bonding electron for oxygen $=2$

Now to adjust and reduce formal charge of chlorine, $3$ oxygen atoms will donate $1$ lone pair. And stabilize the Lewis dot structure.