CHEMISTRY · Multi-part · AP · Chemistry · Compound Structure and Properties · Compound Structure and Properties
Problem
Sulfur dioxide, SO2, is a bent molecule that is commonly described by two major resonance structures in which sulfur is double-bonded to one oxygen atom and single-bonded to the other. In each canonical form, the singly bonded oxygen bears a –1 formal charge, and the sulfur atom has a +1 formal charge. All atoms satisfy the octet rule.
(a) Draw the two major resonance structures for SO2 and assign formal charges to all atoms.
(b) Determine the average S–O bond order in SO2 based on an equal contribution from the resonance structures.
(c) For one canonical resonance structure, count the total number of σ bonds and the total number of π bonds. Then state how many σ and π bonds are present in the resonance hybrid.
(d) Predict whether the S–O bond length in SO2 is closer to that of an S–O single bond or an S=O double bond. Support your prediction with quantitative or qualitative reasoning derived from your answer to part (b).