Question

The formal charges of $C$ and $O$ atoms in $C{O}_2(:\ddot{O}=C=\ddot{O}:)$ are respectively:

• A. $1,-1$
• B. $-1,1$
• C. $2,-1$
• D. $0,0$

Answer 1

The correct option is D $0,0$

$C{O}_2$ is a neutral molecule with 16 total valence electrons. There are three different ways to draw the Lewis structure.
Carbon single bonded to both oxygen atoms (carbon = +2, oxygens = −1 each, total formal charge = 0).
Carbon single bonded to one oxygen and double bonded to another (carbon = +1, oxygendouble = 0, oxygensingle = −1, total formal charge = 0).
Carbon double bonded to both oxygen atoms (carbon = 0, oxygens = 0, total formal charge =0).
Even though all three structures gave us a total charge of zero, the final structure is the superior one because there are no charges in the molecule at all.