# Explain why the bond angle in sulfur dioxide (SO₂) differs from the bond angle in carbon dioxide (CO₂), with reference to electron domains and molecular geometry.

> IB DP Chemistry Higher Level (2023 syllabus) — S2.2 The covalent model · Explain · 4 marks

## Mark scheme (4 marks)

1. CO₂ has two bonding domains (double bonds) and no lone pairs on the central carbon, giving a linear geometry with a bond angle of 180°.
2. SO₂ has two bonding domains and one lone pair on the central sulfur, giving a bent/V-shaped geometry.
3. The lone pair in SO₂ repels the bonding pairs more strongly than bonding pair–bonding pair repulsion, compressing the O–S–O bond angle below 120°.
4. Therefore the bond angle in SO₂ (~119°) is significantly less than in CO₂ (180°) because SO₂ is bent while CO₂ is linear.

## Key terms

- [electron domain](https://www.gradenine.co.uk/glossary/electron-domain)
- [bond angle](https://www.gradenine.co.uk/glossary/bond-angle)

## Related

- [Revision notes for IB DP Chemistry Higher Level (2023 syllabus)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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