91Ó°ÊÓ

The formal charge is the electric charge present on an atom in a molecule. It indicates magnitude and charge, positive or negative.

The formal charge on an atom is equal to the number of valence electrons in a neutral and isolated atom minus the number of electrons present in its bonded atom form in a molecule. The number of electrons in a bonded atom is calculated as half the number of bonding electrons plus the nonbonding, that is, lone-pair electrons.

$\begin{array}{c}\text{Formalcharge=}\left(\begin{array}{l}\text{Numberof}\\ \text{valenceelectrons}\\ \text{infreeatom}\end{array}\right)−\left(\begin{array}{l}\text{Numberof}\\ \text{valenceelectrons}\\ \text{inbondedatom}\end{array}\right)\\ =\left(\begin{array}{l}\text{Numberof}\\ \text{valence}\\ \text{electron}\\ \text{infreeatom}\end{array}\right)−\left(\frac{\mathrm{Number}\mathrm{of}\text{bondingelectron}}{2}\text{+Numberofnonbondingelectron}\right)\end{array}$

Using the above formula:

$\text{Formalcharge}=\left(\begin{array}{l}\text{Numberof}\\ \text{valence}\\ \text{electron}\\ \text{infreeatom}\end{array}\right)−\left(\frac{\mathrm{Number}\mathrm{of}\text{bondingelectron}}{2}\text{+Numberofnonbondingelectron}\right)$

$\begin{array}{c}=1−\left(\frac{2}{2}+0\right)\\ =1−1\\ =0\end{array}$

Using the above formula:

$\text{Formalcharge}=\left(\begin{array}{l}\text{Numberof}\\ \text{valence}\\ \text{electron}\\ \text{infreeatom}\end{array}\right)−\left(\frac{\mathrm{Number}\mathrm{of}\text{bondingelectron}}{2}\text{+Numberofnonbondingelectron}\right)$

$\begin{array}{c}=5−\left(\frac{8}{2}+0\right)\\ =5−4\\ =1\end{array}$

Using the above formula:

$\text{Formalcharge}=\left(\begin{array}{l}\text{Numberof}\\ \text{valence}\\ \text{electron}\\ \text{infreeatom}\end{array}\right)−\left(\frac{\mathrm{Number}\mathrm{of}\text{bondingelectron}}{2}\text{+Numberofnonbondingelectron}\right)$

$\begin{array}{c}=6−\left(\frac{2}{2}+6\right)\\ =6−7\\ =−1\end{array}$

Using the above formula:

$\text{Formalcharge}=\left(\begin{array}{l}\text{Numberof}\\ \text{valence}\\ \text{electron}\\ \text{infreeatom}\end{array}\right)−\left(\frac{\mathrm{Number}\mathrm{of}\text{bondingelectron}}{2}\text{+Numberofnonbondingelectron}\right)$

$\begin{array}{c}=4−\left(\frac{8}{2}+0\right)\\ =4−4\\ =0\end{array}$

Using the above formula:

$\text{Formalcharge}=\left(\begin{array}{l}\text{Numberof}\\ \text{valence}\\ \text{electron}\\ \text{infreeatom}\end{array}\right)−\left(\frac{\mathrm{Number}\mathrm{of}\text{bondingelectron}}{2}\text{+Numberofnonbondingelectron}\right)$

$\begin{array}{c}=5−\left(\frac{4}{2}+4\right)\\ =5−6\\ =−1\end{array}$

Using the above formula:

$\text{Formalcharge}=\left(\begin{array}{l}\text{Numberof}\\ \text{valence}\\ \text{electron}\\ \text{infreeatom}\end{array}\right)−\left(\frac{\mathrm{Number}\mathrm{of}\text{bondingelectron}}{2}\text{+Numberofnonbondingelectron}\right)$

$\begin{array}{c}=5−\left(\frac{8}{2}+0\right)\\ =5−4\\ =1\end{array}$

Using the above formula:

$\text{Formalcharge}=\left(\begin{array}{l}\text{Numberof}\\ \text{valence}\\ \text{electron}\\ \text{infreeatom}\end{array}\right)−\left(\frac{\mathrm{Number}\mathrm{of}\text{bondingelectron}}{2}\text{+Numberofnonbondingelectron}\right)$

$\begin{array}{c}=4−\left(\frac{8}{2}+0\right)\\ =4−4\\ =0\end{array}$

Using the above formula:

$\text{Formalcharge}=\left(\begin{array}{l}\text{Numberof}\\ \text{valence}\\ \text{electron}\\ \text{infreeatom}\end{array}\right)−\left(\frac{\mathrm{Number}\mathrm{of}\text{bondingelectron}}{2}\text{+Numberofnonbondingelectron}\right)$

$\begin{array}{c}=5−\left(\frac{6}{2}+2\right)\\ =5−5\\ =0\end{array}$

Using the above formula:

$\text{Formalcharge}=\left(\begin{array}{l}\text{Numberof}\\ \text{valence}\\ \text{electron}\\ \text{infreeatom}\end{array}\right)−\left(\frac{\mathrm{Number}\mathrm{of}\text{bondingelectron}}{2}\text{+Numberofnonbondingelectron}\right)$

$\begin{array}{c}=5−\left(\frac{2}{2}+4\right)\\ =5−5\\ =0\end{array}$

Using the above formula:

$\text{Formalcharge}=\left(\begin{array}{l}\text{Numberof}\\ \text{valence}\\ \text{electron}\\ \text{infreeatom}\end{array}\right)−\left(\frac{\mathrm{Number}\mathrm{of}\text{bondingelectron}}{2}\text{+Numberofnonbondingelectron}\right)$

$\begin{array}{c}=5−\left(\frac{8}{2}+0\right)\\ =5−4\\ =1\end{array}$

Using the above formula:

$\text{Formalcharge}=\left(\begin{array}{l}\text{Numberof}\\ \text{valence}\\ \text{electron}\\ \text{infreeatom}\end{array}\right)−\left(\frac{\mathrm{Number}\mathrm{of}\text{bondingelectron}}{2}\text{+Numberofnonbondingelectron}\right)$

$\begin{array}{c}=4−\left(\frac{8}{2}+0\right)\\ =4−4\\ =0\end{array}$

Using the above formula:

$\text{Formalcharge}=\left(\begin{array}{l}\text{Numberof}\\ \text{valence}\\ \text{electron}\\ \text{infreeatom}\end{array}\right)−\left(\frac{\mathrm{Number}\mathrm{of}\text{bondingelectron}}{2}\text{+Numberofnonbondingelectron}\right)$

$\begin{array}{c}=5−\left(\frac{4}{2}+4\right)\\ =5−6\\ =−1\end{array}$