# calculate the formal charges of the atoms in CO, CO2, and CO3(-2)?

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• Formal charges ....

Formal charges are assigned to individual atoms in a compound. Formal charges are not actual charges, they are hypothetical charges, assuming that all of the bonds are 100% covalent (Similarly, oxidation states are hypothetical charges assuming that all the bonds are 100% ionic.  There are no 100% ionic bonds.)  The sum of the formal charges must equal the total charge on the particle, zero for a compound, the ioniz charge for a polyatomic ion.

Formal charge = valence electrons - nonbonding electrons - 1/2 bonding electrons

FC = VE - NBE - 1/2BE

:C≡O: ....... FC of C = 4 - 2 - 3 = -1...... FC of O = 6 - 2 - 3 = +1

O=C=O .... FC of C = 4 - 0 - 4 = 0 ...... FC of O = 6 - 4 - 2 = 0

O−C=O (2-) .... plus two additional resonance structures

......|

.....O

FC of C = 4 - 0 - 4 = 0

FC of O in C=O = 6 - 4 -2 = 0

FC of O in C−O = 6 - 6 - 1 = -1 ..... Since there are two of these oxygen atoms, the total of the FCs equals the charge on the ion, -2.