Question

Draw a valid Lewis structure for the molecule CH₃NO in which there are no nonzero formal charges on any of the atoms. This structure should not include any bonds between N and O.

Answer 1

Fhe given molecule with formula, CH3NO where no bond between N and O can be written as formamide as shown below:

Now having written the structural formula for the given molecular formula we can calculate formal charges on each atom as shown below:

Formal Charges (FC) = Number of valence electrons for the atom (V) - number of electrons in lone pairs (N) - 1/2 (number of electrons in bond pairs, B)​

FC = V - N - B/2

Hence we need to calculate valence electrons, electrons in lone pairs​ and number of electrons in bond pairs​ for each atom in the above molecule.

Valance electrons (V)
on C = 4e
on H = 1e
on N = 5e
on O = 6e

electrons in lone pairs (N)

on C = 0e
on H = 0e
on N = 2e
on O = 4e

number of electrons in bond pairs (B)

for C = 8e

for H = 2e

for N = 6e

for O = 4e

Calculation of formal charges for each (C, H, N, O) are given as follows:

C = 4 - 0 - (8/2) = 0

H = 1 - 0 - (2/2) = 0

N = 5 -2 - (6/2) = 0

O = 6 - 4 - (4/2) = 0

Lewis dot structure for the given molecule is shown below:

=