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CAIE IGCSE Chemistry Alloy Hardness and Atomic Layers

CAIE IGCSE Chemistry Alloy Hardness and Atomic Layers
Cambridge IGCSE Chemistry 0620 syllabus for exams in 2026, 2027 and 20282026–2028

Practise explaining alloy hardness and strength using differently sized atoms that disrupt regular metal layers and make sliding more difficult.

How this is tested

  • state that an alloy contains atoms of different sizes within the metal lattice
  • explain that the distorted layers cannot slide past one another as easily as in a pure metal
  • link more difficult layer movement to greater hardness, strength and reduced malleability

Question 5(c)

[Maximum number: 2]

This question is about iron.

Most iron is converted into steel. Steel is an alloy.

Steel is more useful than pure iron because it is harder and stronger.
Explain why the structure of alloys causes them to be harder and stronger than pure metals.
You may include a diagram as part of your answer.