Consider the following resonance structure for carbon dioxide: O=C=O with one oxygen atom bearing a negative charge and the carbon atom bearing a positive charge. How significant is this resonance structure in contributing to the overall electronic structure of CO2?

• A. It is a minor contributor because it places a positive charge on the highly electronegative oxygen atom.
• B. It is a minor contributor because it places a positive charge on the less electronegative carbon atom and a negative charge on oxygen, which is more electronegative.
• C. It is a major contributor because it distributes charges evenly across all atoms.
• D. It is the only significant resonance structure for CO2.

Answer: (B)

Verified step by step guidance

1. Identify the resonance structure given: O=C=O with one oxygen bearing a negative charge and the carbon bearing a positive charge.
2. Recall the concept of electronegativity: oxygen is more electronegative than carbon, meaning oxygen atoms tend to attract electrons more strongly.
3. Evaluate the placement of charges in the resonance structure: a positive charge on carbon (less electronegative) and a negative charge on oxygen (more electronegative) is more stable than the reverse.
4. Understand that resonance structures with charges placed on atoms consistent with their electronegativity are more significant contributors to the resonance hybrid.
5. Conclude that this resonance structure is a minor contributor because it places a positive charge on carbon and a negative charge on oxygen, which is consistent with electronegativity trends, but the overall neutral structure without charges is usually the major contributor.