Chapter Overview
Materials can be compared through observable properties. Metals and non-metals show broad patterns, but scientific classification also recognises exceptions.
The chapter follows an enquiry-based approach: observe carefully, distinguish evidence from explanation, use appropriate units and communicate conclusions honestly.
Learning Objectives
After studying this chapter, you should be able to:
- explain metallic properties in clear scientific language;
- explain non-metallic properties in clear scientific language;
- explain reactions with oxygen in clear scientific language;
- explain uses and choice of material in clear scientific language;
- connect scientific ideas with familiar situations;
- plan or evaluate a safe and fair investigation.
Key Concepts
| Concept | Explanation | |---|---| | Metallic properties | Many metals are lustrous, malleable, ductile, sonorous and good conductors of heat and electricity. | | Non-metallic properties | Many solid non-metals are dull and brittle and conduct poorly, although exceptions such as graphite exist. | | Reactions with oxygen | Many metals form metal oxides and many non-metals form non-metal oxides. Their behaviour in water differs. | | Uses and choice of material | A material is selected for a purpose by matching properties such as strength, conductivity, flexibility and resistance to corrosion. |
Detailed Explanation
Metallic properties
Many metals are lustrous, malleable, ductile, sonorous and good conductors of heat and electricity.
Non-metallic properties
Many solid non-metals are dull and brittle and conduct poorly, although exceptions such as graphite exist.
Reactions with oxygen
Many metals form metal oxides and many non-metals form non-metal oxides. Their behaviour in water differs.
Uses and choice of material
A material is selected for a purpose by matching properties such as strength, conductivity, flexibility and resistance to corrosion.
A scientific statement should be supported by observations, measurements or a tested explanation. Record unexpected results instead of hiding them.
Investigation
Compare teacher-provided samples for lustre, sonority and electrical conductivity. Do not strike, heat or chemically test unknown materials without supervision.
For a fair test, identify what is changed, what is measured, and which important conditions are kept the same. Record results before interpreting them.
Important Definitions
- Metallic properties: Many metals are lustrous, malleable, ductile, sonorous and good conductors of heat and electricity.
- Non-metallic properties: Many solid non-metals are dull and brittle and conduct poorly, although exceptions such as graphite exist.
- Reactions with oxygen: Many metals form metal oxides and many non-metals form non-metal oxides. Their behaviour in water differs.
- Uses and choice of material: A material is selected for a purpose by matching properties such as strength, conductivity, flexibility and resistance to corrosion.
Use precise terms, labelled diagrams where relevant, and complete cause-and-effect statements. A correct scientific reason is more useful than a one-word answer.
Common Mistakes
- Claiming every metal is hard or every non-metal is dull.
- Confusing malleability with ductility.
- Choosing a material by appearance alone rather than the required property.
Quick Revision
- Metallic properties: Many metals are lustrous, malleable, ductile, sonorous and good conductors of heat and electricity.
- Non-metallic properties: Many solid non-metals are dull and brittle and conduct poorly, although exceptions such as graphite exist.
- Reactions with oxygen: Many metals form metal oxides and many non-metals form non-metal oxides.
- Uses and choice of material: A material is selected for a purpose by matching properties such as strength, conductivity, flexibility and resistance to corrosion.
Practice Questions
- What is malleability?
- What is ductility?
- Why is copper used in electrical wiring?
- Name a conducting non-metal.
Answers and Explanations
- The ability to be beaten into thin sheets.
- The ability to be drawn into wires.
- It conducts electricity well and is ductile.
- Graphite.
Apply Your Learning
Find one example of this chapter’s science in your home, school or neighbourhood. Describe what you observe, propose an explanation, and state what additional evidence would test that explanation.