How do you draw the Lewis structure of SO₂?

SO₂ has 18 valence electrons. Sulfur is central, bonded to two oxygens. Two single bonds use 4 electrons; 14 remain. Distribute remaining: 3 lone pairs on each O (12 e⁻) + 1 lone pair on S (2 e⁻) = 14. S only has 6 electrons — needs more.

Does SO₂ have resonance structures?

Yes, SO₂ has 2 resonance structures.

Lewis Structure of SO₂ (Sulfur Dioxide)

What is the Lewis structure of SO₂?

SO₂ has 18 valence electrons, 3 bonding electron pairs, and 6 lone pairs. SO₂ has 18 valence electrons and two resonance structures. The double bond alternates between the two S–O bonds, giving each a bond order of 1.5. The central S has FC = +1 and one terminal O has FC = -1.

Lewis structure of SO₂ (Sulfur Dioxide)

Formula	SO₂
Name	Sulfur Dioxide
Total Valence Electrons	18
Lone Pairs	6
Has Resonance	Yes
Resonance Structures	2
Concept	Resonance
Difficulty	Intermediate

Step 1: Count Valence Electrons

S (Group 6A) has 6, each O has 6: 6 + 6 + 6 = 18 total.

Step 2: Draw the Skeleton

Sulfur is central, bonded to two oxygens. Two single bonds use 4 electrons; 14 remain.

Step 3: Distribute Lone Pairs

Distribute remaining: 3 lone pairs on each O (12 e⁻) + 1 lone pair on S (2 e⁻) = 14. S only has 6 electrons — needs more.

Step 4: Form Multiple Bonds

Convert 1 lone pair from an O to a π bond, forming one S=O double bond. S now has 8 electrons.

Step 5: Check Formal Charges

S (central): FC = 6 - 2 - ½(6) = +1
O (single bond): FC = 6 - 6 - ½(2) = -1
O (double bond): FC = 6 - 4 - ½(4) = 0
Two resonance structures swap which O has the double bond.

Resonance Structures

SO₂ has 2 resonance structures. The actual electronic structure is a hybrid of all resonance contributors.

Resonance structure 2

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