Starter quiz
- Which of the following diagrams models the arrangement of particles in a metal?
- Which of the following are common physical properties of metals?
- low melting point
- ductile ✓
- malleable ✓
- brittle
-
- Match the following physical properties of metals with the corresponding reasons for each property.
- ductile and malleable⇔Ions are arranged in layers that can easily slide over each other. ✓
- good thermal and electrical conductors⇔Ions are surrounded by a 'sea' of delocalised electrons. ✓
- high melting points⇔Strong electrostatic attraction between ions (+) and electrons (–). ✓
- Metallic structures consist of ______ surrounded by __________.
- positive metal ions ✓
- a 'sea' of delocalised electrons ✓
- negative metal ions
- metal atoms
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- Which force of attraction binds together the particles in a giant metallic structure?
- 'electrostatic' ✓
- Metals are malleable because...
- they can be hammered into shape without breaking. ✓
- they can be pulled into wire.
- the layers of metal ions can easily slide over each other. ✓
- they contain delocalised electrons.
-
Exit quiz
- Match the following key terms to their definitions.
- alloy⇔A mixture of two or more elements, at least one of which is a metal. ✓
- delocalised electron⇔Negatively charged particle free to move through the metal structure. ✓
- molten⇔A liquid substance formed by heating solid metal, glass or rocks. ✓
- physical poperty⇔A characteristic of a substance that can be observed or measured. ✓
- A metallic bond is a strong electrostatic force of attraction between the positively charged ______ and the delocalised electrons in a metal.
- 'metal ions' ✓
- True or false? Alloys have a disrupted or irregular lattice structure.
- True ✓
- False
- Which of the following statements about pure metals and alloys are correct?
- Most alloys are more ductile than pure metals.
- Most alloys are less malleable than pure metals. ✓
- Alloys and pure metals are both good electrical conductors. ✓
- Most alloys are poor thermal conductors.
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- Aluminium atoms form Al³⁺ ions and lithium atoms form Li⁺ ions. Which of the following statements about aluminium and lithium ions are correct?
- Lithium atoms gain one electron to form lithium ions.
- Aluminium ions and lithium ions are the same size.
- Aluminium contains more delocalised electrons per ion than lithium. ✓
- Aluminium atoms lose three electrons to form aluminium ions. ✓
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- The melting point of a substance is an example of a ______ property.
- 'physical' ✓
Worksheet
Presentation
Video
Lesson Details
Key learning points
- In pure metals, ions are arranged in a regular structure with delocalised electrons between them
- If a metal is stretched or forced out of shape, its ions are able to move position without the metallic bonds breaking
- An alloy is a mixture of different metal elements or of metals with non metal elements (i.e. carbon)
- Ions of different metal elements may be different sizes and have different electrical charges
- The structure of an alloy is not as regular as a pure metal and this affects its properties
Common misconception
The metallic structure model is a replication of reality. Therefore, metals contain seawater. The concept of electric current is challenging. Some may think that electrons jump from atom to atom.
Discuss why scientists use models with the pupils, explaining that a model is only as good as what it can explain, so it develops over time. Remind pupils how an electric circuit works before discussing why metals are good conductors.
Keywords
Alloy - An alloy is a mixture of two or more elements, where at least one element is a metal.
Physical properties - A physical property is a characteristic of a substance that can be observed or measured. For example, the temperature at which a substance melts.
Delocalised electron - Electrons are said to be delocalised when they are free to move through the structure of a metal and can carry an electrical current.
Molten - Molten is the term used to describe a liquid substance formed by heating solid metals, glass, or rocks.