Answer
a. -1
b. -1, 1, -1 (from left to right)
c. 1
d. 0, 0 (from left to right)
Work Step by Step
To calculate the formal charge of each atom, use the following formula:
number of valence electrons - [number of unshared electrons + $(\frac{1}{2})$(number of shared electrons)]
a. $5-[4+(\frac{1}{2})(4)] = -1$
b. $5-[4+(\frac{1}{2})(4)] = -1$
$5-[0+(\frac{1}{2})(8)] = 1$
$5-[4+(\frac{1}{2})(4)] = -1$
c. $6-[2+(\frac{1}{2})(6)] = 1$
d. $5-[2+(\frac{1}{2})(6)] = 0$
$6-[4+(\frac{1}{2})(4)] = 0$
