Chapter 1 Sapling

Question 17 of chapter 1 asks for the formal charges on the nitrogen atom. The formula used to calculate formal charge is 

[# of valence electrons – (# of lone pairs+1/2 bonding electrons)]

For the first structure, the nitrogen atom has 5 valence electrons, no lone pairs and 8 bonding electron. The formula will be [5-(0+1/2 8)] which equals 1 = +. 

For the second structure, the nitrogen atom has 5 valence electrons, 2 lone pairs and 6bonding electron. The formula will be [5-(2+1/2 6)] which equals 0.

For the third structure, the nitrogen atom has 5 valence electrons, 2 lone pairs and 6bonding electron. The formula will be [5-(2+1/2 6)] which equals 0.

For the fourth structure, the nitrogen atom has 5 valence electrons, 2 lone pairs and 6bonding electron. The formula will be [5-(2+1/2 6)] which equals 0.

For the fifth structure, the nitrogen atom has 5 valence electrons, no lone pairs and 8 bonding electron. The formula will be [5-(0+1/2 8)] which equals 1 = +. 

For the sixth structure, the nitrogen atom has 5 valence electrons, 2 lone pairs and 8 bonding electrons. The formula will be [5-(4+1/2 4)] which equals -1. The result is a negative charge. 

For the seventh structure, the nitrogen atom has 5 valence electrons, 2 lone pairs and 6bonding electron. The formula will be [5-(2+1/2 6)] which equals 0.