# How would you determine the formal charges on each atom in the carbonate ion (CO_3^(2-))?

$C {O}_{3}^{2 -}$ has $3 \times 6 + 4 + 2 = 24 \text{ valence electrons}$ to distribute around 4 centres.
A Lewis structure of $O = C {\left(- {O}^{-}\right)}_{2}$ gives a neutral doubly oxygen, a neutral carbon, and 2 anionic oxygen atoms associated with 7 valence electrons. Of course, I can draw resonance structures to show the equality of the oxygen atoms.