Starter quiz
- Which of the following best describes an alloy?
- A mixture ✓
- A compound
- An element
- An atom
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- Metallic bonding consists of metal ions in a 'sea' of ______.
- 'delocalised electrons' ✓
- Why are pure metals ductile?
- Metal ions are arranged in layers that can slide over one another. ✓
- Delocalised electrons are free to move through the metal.
- Strong electrostatic attraction between metal ions and delocalised electrons.
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- Is this statement true or false? Pure metals are generally more malleable than their alloy counterparts.
- True ✓
- False
- What is 25% of 50.0? Give your answer to 3 significant figures.
- '12.5' ✓
- Why do metals have high melting points?
- Metal ions are arranged in layers that can slide over one another.
- Delocalised electrons are free to move through the metal.
- Strong electrostatic attraction between metal ions and delocalised electrons. ✓
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Exit quiz
- Match the following terms to the correct definition.
- Carat⇔a measure of the purity of gold ✓
- Brittle⇔hard but breaks easily ✓
- Steel⇔alloy of iron ✓
- Which two metals are found in the alloy bronze?
- Copper ✓
- Tin ✓
- Zinc
- Iron
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- Which of the following statements about steel are correct?
- Steel is harder than pure iron. ✓
- Steel is more malleable than pure iron.
- Steel is more ductile than pure iron.
- Steel is more resistant to corrosion than pure iron. ✓
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- Which of the following are examples of alloys?
- 18-carat gold ✓
- Brass ✓
- Zinc
- 24-carat gold
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- A 0.500 kg piece of copper alloy contains 27% aluminium. What mass of aluminium does it contain? Give your answer to three significant figures.
- '0.135 kg' ✓
- Why do metal alloys usually have lower melting points than the metals they are made from?
- There are different sized ions in the structure. ✓
- There are delocalised electrons in the structure.
- The bonds between the ions and electrons are weaker. ✓
- There is a regular lattice structure.
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Worksheet
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Presentation
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Lesson Details
Key learning points
- Iron is alloyed with other metals to produce steel alloys.
- Copper is alloyed with other metals to make multiple useful alloys.
- Gold, aluminium, and magnesium all form useful alloys with other metals.
Common misconception
Pupils often find it difficult to apply what they have learnt about alloys when asked about an unfamiliar one, or when provided with a table of data.
Provide pupils with a range of different examples of alloys. Give them plenty of practice of comparing the properties of the alloy with those of the pure metal.
Keywords
Alloy - A mixture of two or more elements, where at least one element is a metal.
Steel - An alloy of iron that contains specific amounts of carbon and may contain other metals.
Carat - A unit for measuring the purity of gold.
Brittle - A substance that has the ability to break up easily.
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