How many valid resonance structures can be drawn for the ozone molecule (O_3)?

• A. 3
• B. 4
• C. 2
• D. 1

Answer: (C)

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 atoms.
2. Draw the Lewis structure of ozone (O_3) by first counting the total valence electrons: each oxygen atom has 6 valence electrons, so total electrons = 3 \times 6 = 18.
3. Arrange the three oxygen atoms in a row and connect them with single bonds initially. Then distribute the remaining electrons to satisfy the octet rule as much as possible.
4. Identify possible resonance structures by moving the double bond between different pairs of oxygen atoms while keeping the overall connectivity the same. For ozone, this results in two valid resonance structures where the double bond shifts between the left and right oxygen atoms.
5. Confirm that both resonance structures have the same total number of valence electrons and that the formal charges are minimized and consistent with the known structure of ozone.