Which of the following molecules exhibits resonance?

• A. ${\mathrm{NH}}_3$ (ammonia)
• B. $H_{2}O$ (water)
• C. ${\mathrm{CH}}_4$ (methane)
• D. $O_3$ (ozone)

Answer: (D)

Verified step by step guidance

1. Understand that resonance occurs when a molecule can be represented by two or more valid Lewis structures that differ only in the placement of electrons, not atoms.
2. Draw the Lewis structures for each molecule: ammonia (NH\_3), water (H\_2O), methane (CH\_4), and ozone (O\_3).
3. For ammonia, water, and methane, check if there are alternative Lewis structures with different electron arrangements that maintain the octet rule and atom connectivity. Typically, these molecules have fixed single bonds and lone pairs without delocalized electrons.
4. For ozone (O\_3), identify that it has a resonance structure because the double bond and single bond between oxygen atoms can switch positions, creating multiple valid Lewis structures with delocalized pi electrons.
5. Conclude that ozone exhibits resonance due to the delocalization of electrons over the oxygen atoms, while ammonia, water, and methane do not have resonance structures.