Question #cd215

1 Answer
Apr 8, 2015

The carbonate ion, or #CO_3^(2-)#, has a total of 24 valence electrons, 4 from carbon, 6 from each of the three oxygen atoms, and 2 additional ones.

Three equivalent Lewis structures, also called resonance structures, can be drawn for the carbonate ion

http://chem-net.blogspot.ro/2012/01/simple-procedure-for-writing-lewis.html

The molecule's Lewis structure (you can pick any of the three structures shown above, since they're all equivalent) has a total of 8 lone pairs of electrons and 8 bonding electrons.

As you can see, the central carbon atom has zero lone pairs of electrons and uses all its 4 valence electrons to form bonds with three oxygen atoms: 2 single bonds and 1 double bond.

The carbon atom obeys the octet rule because it has 8 electrons in its valence shell, 2 for each bond it has with the oxygen atoms.