Select the Lewis Dot structure or structures that properly predict the formulation for SO2: You may select multiple answers. a) O-S-O b) O=S=O c) :O-S-O; d) :O-S-O
The Correct Answer and Explanation is:
Correct Answer:
✅ b) O=S=O
✅ c) :O–S–O
✅ d) :O–S=O (Assuming a resonance structure was meant here)
Explanation
Sulfur dioxide (SO₂) is a chemical compound consisting of one sulfur (S) atom and two oxygen (O) atoms. To determine the correct Lewis dot structures, we must consider the valence electrons, octet rule, and formal charges to draw the most accurate representations of bonding.
Step 1: Count total valence electrons
- Sulfur (S) has 6 valence electrons.
- Oxygen (O) has 6 valence electrons × 2 = 12.
- Total = 18 valence electrons
Step 2: Choose a central atom
Sulfur is less electronegative than oxygen, so it serves as the central atom.
Step 3: Arrange atoms
Attach the two oxygen atoms to the sulfur atom with single bonds initially. This uses up 4 electrons (2 bonds × 2 electrons).
Remaining: 18 – 4 = 14 electrons to be placed as lone pairs.
Distribute electrons to fulfill the octets of the oxygen atoms and then sulfur. After distributing, we find that formal charges are not optimized. So, we form double bonds between sulfur and one or both oxygens to reduce formal charges and better reflect reality.
Resonance Structures of SO₂:
- O=S–O⁻
- ⁻O–S=O
- O=S=O
These resonance forms share characteristics. The real structure is a hybrid where both S–O bonds are between a single and double bond — about 1.5 bond order.
Thus, valid Lewis structures include:
- (b) O=S=O (complete octets, neutral formal charges)
- (c) :O–S–O (likely with lone pairs, possibly a resonance contributor)
- (d) :O–S=O (another resonance form)
(a) O–S–O is not valid if it lacks lone pairs or formal charges, and does not satisfy the octet rule or represent the resonance.
Therefore, the correct Lewis Dot structures that predict SO₂ formulation are (b), (c), and (d).
