Metal alloys
I can evaluate the metallic structure model in terms of its ability to explain some physical properties of metals and metal alloys.
Metal alloys
I can evaluate the metallic structure model in terms of its ability to explain some physical properties of metals and metal alloys.
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.
Equipment
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Video
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Starter quiz
6 Questions
Ions are arranged in layers that can easily slide over each other.
Ions are surrounded by a 'sea' of delocalised electrons.
Strong electrostatic attraction between ions (+) and electrons (–).
Exit quiz
6 Questions
A mixture of two or more elements, at least one of which is a metal.
Negatively charged particle free to move through the metal structure.
A liquid substance formed by heating solid metal, glass or rocks.
A characteristic of a substance that can be observed or measured.