Question

In the following electron-dot structure, calculate the formal charge on each nitrogen atom from left to right.

• A. -1, -1, +1
• B. -1, +1, -1
• C. +1, -1, -1
• D. +1, -1, +1

Answer 1

Answer: (B)

Formal charge on an atom
= total no. of valence electrons in the free atom - total no. of non-bonding electrons $-\frac{1}{2}\times$ total no. of bonding electrons
$N^1=5-4-\frac{1}{2}\times 4=5-6=-1$
$N^2=5-0-\frac{1}{2}\times 8=5-4=+1$
$N^3=5-4-\frac{1}{2}\times 4=-1$