Final answer:
The bicarbonate ion, HCO3-, has three resonance structures with carbon-oxygen double bond in different positions. The actual arrangement of electrons in the bicarbonate ion is the average of the three resonance structures.
Step-by-step explanation:
The bicarbonate ion, HCO3-, has three resonance structures.
Resonance structures are different representations of the same molecule or ion that differ only in the arrangement of electrons. In the case of the bicarbonate ion, the three resonance structures are represented by the different positions of the carbon-oxygen double bond. Each resonance structure has a bond order of 1.33 for the carbon-oxygen bonds.
This means that the actual arrangement of electrons in the bicarbonate ion is the average of the three resonance structures, and all three carbon-oxygen bonds are exactly the same in length.