Which of the following species exhibits resonance?

• A. O3
• B. CH4
• C. CO2
• D. H2O

Answer: (A)

Verified step by step guidance

1. Understand that resonance occurs when a molecule or ion can be represented by two or more valid Lewis structures that differ only in the placement of electrons, not atoms.
2. Examine each species' Lewis structure to see if multiple valid resonance forms exist:
3. For CH4 (methane), draw the Lewis structure with carbon in the center and four single bonds to hydrogen atoms. There are no alternative electron arrangements, so no resonance.
4. For CO2 (carbon dioxide), draw the Lewis structure with carbon double bonded to two oxygen atoms. Although there are double bonds, the structure is symmetrical and does not have alternative resonance forms that differ in electron placement.
5. For O3 (ozone), draw the Lewis structures showing one double bond and one single bond between oxygen atoms, with the double bond position alternating between the two outer oxygens. This indicates resonance because the actual structure is a hybrid of these forms.