Answer
Sodium has a formal charge of +1 and Boron has a formal charge of -1. Both charges cancel each other and give a overall charge of 0.
Work Step by Step
Formal Charge (FC) = [number of valence electrons] - [number of non-bonding electrons] - 1/2 [shared electrons]
FC (Boron) = 3-0-4 = -1
FC (carbon) = 4-0-4 = 0
FC (nitrogen) = 5-2-3 = 0
FC (sodium) = 1-0-0 = +1
