Question

determine the formal charge on the nitrogen atom in each of the structures.

all nonbonding electrons are shown.

what is the formal charge on the nitrogen atom in structure a?
+
0
-
what is the formal charge on the nitrogen atom in structure b?
+
0
-

Explanation:

For Structure A (NH₃ - attached to benzene ring)

Step1: Recall formal charge formula

The formula for formal charge (\(FC\)) is \(FC = V - N - \frac{B}{2}\), where \(V\) is the number of valence electrons in the neutral atom, \(N\) is the number of non - bonding electrons, and \(B\) is the number of bonding electrons. For nitrogen, \(V = 5\).
In structure A, the nitrogen atom is bonded to 3 hydrogen atoms (so \(B=6\), since each single bond has 2 electrons) and has 0 non - bonding electrons (\(N = 0\)).

Step2: Calculate formal charge

Substitute into the formula: \(FC=5 - 0-\frac{6}{2}=5 - 0 - 3 = 0\).

Step1: Recall formal charge formula

Using the same formula \(FC = V - N-\frac{B}{2}\), with \(V = 5\) for nitrogen.
In structure B, the nitrogen atom is bonded to 2 hydrogen atoms (so \(B = 4\), as each single bond has 2 electrons) and has 2 non - bonding electrons (\(N=2\)).

Step2: Calculate formal charge

Substitute into the formula: \(FC = 5-2-\frac{4}{2}=5 - 2-2 = 0\).

Answer:

0 (corresponding to the option "0")

For Structure B (NH₂ - attached to benzene ring)