Ozone, O₃, plays a dual role in Earth’s atmosphere by absorbing harmful ultraviolet…
CHEMISTRY · Multi-part · AP · Chemistry · Compound Structure and Properties · Compound Structure and Properties
Problem
Ozone, O₃, plays a dual role in Earth’s atmosphere by absorbing harmful ultraviolet radiation while acting as a pollutant in the lower troposphere. Three candidate Lewis diagrams for O₃ are proposed.
• Diagram I: O₁ double-bonded to O₂; O₂ single-bonded to O₃. All atoms have lone pairs needed for octets.
• Diagram II: O₁ single-bonded to O₂; O₂ double-bonded to O₃. All atoms have lone pairs needed for octets.
• Diagram III: O₁ single-bonded to O₂; O₂ single-bonded to O₃; the central O₂ atom possesses one lone pair instead of two (6 valence electrons on O₂), resulting in no formal charges.
Use these diagrams to answer the questions below.
(a) Construct a formal-charge table for each atom in Diagrams I, II, and III. Show all work leading to the numerical values.
(b) Identify any violations of the octet rule in each diagram.
(c) Rank the three diagrams in order of decreasing plausibility, providing a detailed rationale that integrates your findings from parts (a) and (b).
(d) Combine the dominant plausible diagrams into a resonance hybrid. Using this hybrid, predict whether the two O–O bond lengths in ozone will be identical, different, or indeterminate relative to typical O–O single and double bonds. Explain your reasoning.
(e) The experimentally determined average O–O bond length in ozone is 128 pm. Rationalize this value in the context of your prediction in part (d).