Question

Draw the lewis structure of ch3nc; fill in any nonbonding electrons. Calculate the formal charge on each atom other than hydrogen.

Answer 1

A visual representation of covalent bonding which represents the valence shell electrons in the molecule is said to be a Lewis structure. The lines represents the shared electron pairs and dots represents the electrons that are not involved in the bonding i.e lone pairs.

Number of valence electrons in each atom:

For Carbon, $C$ = 4

For Hydrogen, $H$ = 1

For Nitrogen, $N$ = 5

The Lewis structure of $CH_3NC$ is shown in the attached image.

The formula of calculating formula charge = $FC = VE - NE- \frac{BE}{2}$   -(1)

where, F.C is formal charge, V.E is number of valence electrons, N.E is number of non-bonding electrons and B.E is number of bonding electrons.

Now, calculating the formal charge:

For $C$ on left side:

$FC = 4 - 0- \frac{8}{2} = 0$

For $N$:

$FC = 5 - 0- \frac{8}{2} = +1$

For $C$ on right side:

$FC = 4 - 2- \frac{6}{2} = -1$

The formula charge of each atom other than hydrogen is shown in the attached image.