Question

Calculate the formal charge on so2

Answer 1

Formal Charge= Valence electron- Non bonded - bonded/2

Answer 2

Answer :  The formal charge on sulfur and two oxygen atom $S,O_1\text{ and }O_2$ are +1, 0 and -1 respectively.

Explanation :  

First we have to draw resonance structure of, $SO_2$.

As we know that sulfur and oxygen has '6' valence electrons.

Therefore, the total number of valence electrons in, $SO_2$ = 3(6) = 18

Now we have to calculate the formal charges on sulfur and two oxygen atom.

Formula for formal charge :

$\text{Formal charge}=\text{Valence electrons}-\text{Non-bonding electrons}-\frac{\text{Bonding electrons}}{2}$

$\text{Formal charge on }S=6-2-\frac{6}{2}=+1$

$\text{Formal charge on }O_1=6-4-\frac{4}{2}=0$

$\text{Formal charge on }O_2=6-6-\frac{2}{2}=-1$

The resonance structure are shown below.