Draw Lewis structures for each of the following ion: CO3 (2-)

I tried this method below, i do not know where am i going wrong, please help me understand this concept for ions.

Valence Electrons 4e- + 18e- = 22e-
Noble gas Config 8e- + 24e- = 32e-
Total 32e- 22e- = 10e-
Covalent bonds 10e-/2 = 5
Non-Bonding Pairs 22e- - 10e- = 12e-

1 answer

C has 4 electrons, O has 6 electrons + -2 charge adds 2 more electrons
4 + (3 * 6) + 2 = 24 electrons
4 atoms * 8 electrons per atom = 32 electrons
32 โ€“ 24 = 8 electrons
8 electrons รท 2 electrons per bond = 4 bonds

24 โ€“ 8 = 16 electrons
16 electrons = 8 pairs of non-bonding electrons

The carbonate ion, CO32-, has 1 C atom bonded to 3 O atoms with 4 bonds.
2 C โ€“ O bonds and 1 C = O bond, using 4 pair of bonding electrons.