Draw out the Lewis structures for H2CO3, HCO3-, and CO32-. Then determine the maximum number of equivalent resonance structures for each species. Note that carbon is the central atom in all three cases. If the molecule contains hydrogen atoms they are attached to oxygen atoms. Only count the best structures. For example, A structure with really bad formal charges should not be counted.
The molecule H2CO3 has __ equivalent Lewis structures.
The molecule HCO3- has __ equivalent Lewis structures.
The molecule CO32- has ___ equivalent Lewis structures.