Final answer:
In the bicarbonate ion (HCO₃⁻), two equivalent resonance forms can be drawn, with each structure containing 4 sigma bonds and 1 pi bond.
Step-by-step explanation:
For the bicarbonate ion (HCO₃⁻), there are two equivalent resonance forms. In each resonance form, there is one hydrogen atom attached to one of the oxygen atoms.
In one resonance structure, one of the oxygen atoms will have a double bond with carbon, and in the other resonance structure, this double bond can shift to another oxygen atom, illustrating the concept that these resonance structures are a way to represent the true nature of the electron distribution which is a blend of all possible structures.
In terms of bond count, in each resonance structure, there are three sigma bonds (one between the carbon and each of the three oxygens, and, in the case of the bicarbonate ion, one additional sigma bond between the hydrogen and the oxygen to which it is attached).
Additionally, there is one pi bond in each resonance structure, which is between the carbon and the oxygen that has the double bond.
Therefore, counting the bonds in one of the resonance structures, there are a total of 4 sigma bonds and 1 pi bond in the bicarbonate ion.