Question Constellation Sign up for free AQA · GCSE · Combined Science · Higher
Steel and iron hardness
Explain why steel is harder than iron.
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Marking points
- 1 State that carbon atoms are a different size from iron atoms or ions.
- 2 Explain that the different-sized carbon atoms distort the iron layers.
- 3 Link the distorted layers to the layers being unable to slide easily.
Full-mark answer
Carbon atoms are a different size from iron atoms. The carbon atoms distort the layers of iron atoms, so the layers cannot slide over each other easily.