A manufacturer is choosing a material for metal control buttons that must not dent easily. Each sample is tested by applying the same force. A smaller dent depth means that the material is harder.
All atoms of metal M have a diameter of 0.286 nm.
| Sample | Composition | Diameter of added atoms in nm | Dent depth in mm |
|---|---|---|---|
| P | M only | — | 0.48 |
| Q | M and element X | 0.224 | 0.19 |
| R | M and element Y | 0.284 | Not measured |
Explain why the dent depth for sample Q is smaller than for sample P.
Explain whether the dent depth for sample R is likely to be closer to 0.48 mm or 0.19 mm.
84 exam-style questions on AQA GCSE Chemistry 2.2 How bonding and structure are related to the properties of substances, covering 2.2.1a The three states of matter, 2.2.1b Limitations of the simple particle model, 2.2.2 State symbols in chemical equations, 2.2.3 Properties of ionic compounds, 2.2.4 Properties of small molecules, 2.2.5 Polymers, 2.2.6 Giant covalent structures, 2.2.7 Properties of metals and alloys, and 2.2.8 Metals as conductors. Each one has a worked solution and a mark scheme showing where the marks go.