Question

Calculate the formal charge of chlorine in the molecules $\mathrm{C}{\mathrm{l}}_2$, $\mathrm{B}\mathrm{e}\mathrm{C}{\mathrm{l}}_2$, and $\mathrm{C}\mathrm{l}{\mathrm{F}}_5$.

Short answer

The formal charge of $\mathrm{C}\mathrm{l}$ in the compound $\mathrm{C}{\mathrm{l}}_2$ is $0$, $\mathrm{B}\mathrm{e}$ and $\mathrm{C}\mathrm{l}$ in the compound $\mathrm{B}\mathrm{e}\mathrm{C}{\mathrm{l}}_2$ is $0$and, $\mathrm{C}\mathrm{l}$ and $\mathrm{F}$ in the compound $\mathrm{C}\mathrm{l}{\mathrm{F}}_5$ is $0$.

Step-by-step solution

Concept Introduction

A formal charge ($\mathrm{F}.\mathrm{C}.$or$\mathrm{q}$) is the charge on an atom/molecule in covalent bonding, assuming electrons are shared equally in bonds made.

Formal Charge of Chlorine

To find the Formal charge use the formula –

Formal Charge $=$ $($Number of valence electrons on atom) $-$ (non-bonded electrons$+$ Bonding electrons$)$.

Formal Charge for $\mathrm{C}\mathrm{l}$ is:

$\begin{array}{rl}& =\left(7\right)-\left(6+1\right)\\ & =0\end{array}$

The formal charge for$\mathrm{C}{\mathrm{l}}_2$ is found below –

Element	Bonding Electrons	Non-bonded Electrons	Valence Electrons	Formal Charge
$\mathrm{C}\mathrm{l}$	$1$	$6$	$7$	$0$

Therefore, the formal charge for $\mathrm{C}\mathrm{l}$is $0$.

Formal Charge of Beryllium Chloride

To find the Formal charge use the formula –

Formal Charge$=$ $($Number of valence electrons on atom) $-$ (non-bonded electrons $+$ Bonding electrons$)$.

Formal Charge for $\mathrm{B}\mathrm{e}$ is:

$\begin{array}{rl}& =\left(2\right)-\left(0+2\right)\\ & =\end{array}$

Formal Charge for $\mathrm{C}\mathrm{l}$ is:

$\begin{array}{rl}& =\left(7\right)-\left(6+1\right)\\ & =0\end{array}$

The formal charge for $\mathrm{B}\mathrm{e}\mathrm{C}{\mathrm{l}}_2$is found below –

Element	Bonding Electrons	Non-bonded Electrons	Valence Electrons	Formal Charge
$\mathrm{B}\mathrm{e}$	$2$	$0$	$2$	$0$
$\mathrm{C}\mathrm{l}$	$1$	$6$	$7$	$0$

Therefore, the formal charge for$\mathrm{B}\mathrm{e}$ and$\mathrm{C}\mathrm{l}$is$0$.

Formal Charge of Chlorine Pentafluoride

To find the Formal charge use the formula –

Formal Charge $=$ $($Number of valence electrons on atom)$-$ (non-bonded electrons $+$ Bonding electrons$)$.

Formal Charge for$\mathrm{C}\mathrm{l}$ is:

$\begin{array}{rl}& =\left(7\right)-\left(2+5\right)\\ & =0\end{array}$

Formal Charge for $\mathrm{F}$ is:

$\begin{array}{rl}& =\left(7\right)-\left(6+1\right)\\ & =0\end{array}$

The formal charge for$\mathrm{C}\mathrm{l}{\mathrm{F}}_5$ is found below –

Element	Bonding Electrons	Non-bonded Electrons	Valence Electrons	Formal Charge
$\mathrm{C}\mathrm{l}$	$5$	$2$	$7$	$0$
$\mathrm{F}$	$1$	$6$	$7$	$0$

Therefore, the formal charge for $\mathrm{C}\mathrm{l}$ and$\mathrm{F}$is $0$.