# Explain why metals can be drawn into wires (are ductile) and why a metal's electrical conductivity decreases when it is alloyed with another metal of different atomic radius.

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

## Mark scheme (4 marks)

1. In a metal, a lattice of positive ions (cations) is surrounded by / immersed in a 'sea' of delocalised electrons.
2. When a stress is applied, layers of ions can slide past one another without disrupting the overall metallic bonding, because the delocalised electrons can move with the layers and maintain the electrostatic attraction.
3. In a pure metal, electrical conductivity is high because the delocalised electrons can move freely through the regular lattice and carry charge.
4. In an alloy, atoms of different size distort the lattice, which scatters / impedes the flow of delocalised electrons, reducing electrical conductivity.

## Key terms

- [alloy](https://www.gradenine.co.uk/glossary/alloy)
- [electrical conductivity](https://www.gradenine.co.uk/glossary/electrical-conductivity)

## Related

- [Revision notes for IB DP Chemistry Standard 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)

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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-metals-can-be-drawn-6d2e6a45) · Published by Druglandscape Ltd.