# Explain why metals are generally malleable and ductile, whereas ionic compounds are brittle.

> IB DP Chemistry Higher Level (2023 syllabus) — S2.3 The metallic model · Explain · 4 marks

## Mark scheme (4 marks)

1. In metals, positive ions (cations/kernels) are surrounded by a 'sea' of delocalised electrons
2. When a force is applied, layers of metal cations can slide/move past one another without disrupting the bonding, because the delocalised electrons move with the layers and maintain electrostatic attraction throughout
3. In ionic compounds, the lattice contains alternating oppositely charged ions held by strong electrostatic forces in fixed positions
4. When a stress/force is applied to an ionic compound, layers shift so that like charges align, causing strong repulsion between adjacent ions of the same charge, which shatters/cleaves the lattice

## 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)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-metals-are-generally-malleable-e3b44adc) · Published by Druglandscape Ltd.