Answer
a. N: +1
b.
First C: 0
N: +1
Second C: -1
c.
First O: 0
Second O: +1
Third O: -1
Work Step by Step
1. Determine the number of valence of each second row atom:
a. N: 5 electrons.
b. C: 4 electrons, N: 5 electrons.
c. O: 6 electrons.
2. Calculate how many electrons each atom 'has' in the structure.
a. N: 0 + $\frac 12$(8) = 4
b.
First C: 0 + $\frac 12$(8) = 4.
N: 0 + $\frac 12$(8) = 4.
Second C: 2 + $\frac 12$(6) = 5
c.
First O: 4 + $\frac 12$(4) =6
Second O: 2 + $\frac 12$(6) = 5
Third O: 6 + $\frac 12$(2) = 7
3. Use the equation to calculate the formal charge.
a. N: 5 - 4 = +1
b.
First C: 4 -4 = 0
N: 5 - 4 = +1
Second C: 4 - 5 = -1
c.
First O: 6 -6 =0
Second O: 6 - 5 = +1
Third O: 6 - 7 = -1
