Which of the following statements best describes the resonance in the carbonate ion, CO_3^{2-}?

• A. CO_3^{2-} does not exhibit resonance because all bonds are single bonds.
• B. CO_3^{2-} has three equivalent resonance structures, each with one double bond and two single bonds distributed among the oxygen atoms.
• C. CO_3^{2-} has two resonance structures, each with a different arrangement of double bonds.
• D. CO_3^{2-} has only one possible Lewis structure with two double bonds and one single bond.

Answer: (B)

Verified step by step guidance

1. Recall that resonance structures are different Lewis structures for the same molecule that differ only in the placement of electrons, not the arrangement of atoms.
2. Draw the Lewis structure of the carbonate ion, CO_3^{2-}, showing the carbon atom bonded to three oxygen atoms and accounting for the 2- charge by adding extra electrons.
3. Identify that the carbonate ion can be represented by multiple resonance structures where the double bond between carbon and oxygen shifts among the three oxygen atoms.
4. Recognize that these resonance structures are equivalent because each has one C=O double bond and two C–O single bonds, but the position of the double bond changes.
5. Conclude that the best description is that CO_3^{2-} has three equivalent resonance structures, each with one double bond and two single bonds distributed among the oxygen atoms.