Question

Calculate the formal charges on oxygen atoms 1, 2, 3 respectively.

• A. 0, -1, +1
• B. 0, +1, -1
• C. 1, 0, -1
• D. 1, 0, +1

Answer 1

Answer: (C)

1, 0, -1

The formula of formal charge, $FC=V-N-\frac{B}{2}$

where V the number of valence electrons of the neutral atom in isolation (in its ground state); N is the number of non-bonding valence electrons on this atom in the molecule, and B is the total number of electrons shared in bonds with other atoms in the molecule.

The atoms have been numbered as 1, 2, and 3. The formal charge on:
The central O atom marked 1:
$=6-2-\frac{1}{2}\left(6\right)=+1$

The end O atom marked 2:
$=6-4-\frac{1}{2}\left(4\right)=0$

The end O atom marked 3:
$=6-6-\frac{1}{2}\left(2\right)=-1$