4.9Chemistry 01. Materials And Their Structure

Describe the differences between elements, compounds and mixtures,…

5 min read 7 parts Lesson 9 of 11 1 quiz

0%read

Lesson summary

4.9 Elements, compounds and mixtures — CHECKPOINT - Lower Secondary Science 0893 notes: Describe the differences between elements, compounds and mixtures, including air as a mixture and the meaning of pure.Element — a substance made of only one kind of atom.Compound — a substance…

Properties of the elements
Changing composition
Mineral water
Compound — a substance made of two or more different kinds of atoms that are bonded tightly together
Pure — containing only a single substance.Elements and compounds are pure, while a mixture is not pure
Mixture — iron filings stirred with sulfur powder keep their properties.A magnet removes the iron from the mixture

Section 1 of 7Definitions

Element
- a substance made of only one kind of atom.
Compound
- a substance made of two or more different kinds of atoms that are bonded tightly together.
Mixture
- different kinds of particles mixed together without being bonded.
- It can be a mixture of elements, compounds or both.

Section 2 of 7Pure substances

Pure
- containing only a single substance.
- Elements and compounds are pure, while a mixture is not pure.

Section 3 of 7Comparison of elements, compounds and mixtures

Feature	Element	Compound	Mixture
Atoms	One kind only	Different kinds bonded	Different substances not bonded
Properties	Own properties	New properties unlike its elements	Keep the properties of each substance
Separation	Cannot be broken down chemically	Needs a chemical reaction	Physical methods such as a magnet
Example	Iron, sulfur	Iron sulfide	Iron and sulfur mixed, air

Section 4 of 7Iron and sulfur

Mixture
- iron filings stirred with sulfur powder keep their properties.
- A magnet removes the iron from the mixture.
Compound
- heating the mixture makes the compound iron sulfide.
- Iron sulfide is not magnetic and does not conduct heat or electricity.
Properties of the elements
- iron is hard, grey, strong, magnetic and a conductor, while sulfur is yellow, brittle and a non-conductor.

Section 5 of 7Air as a mixture

Gas	Approximate percentage
Nitrogen	78%
Oxygen	21%
Carbon dioxide, argon, water vapour and others	1%

Changing composition
- the amount of water vapour changes with the weather.
- Respiration, burning fossil fuels and photosynthesis change the amount of carbon dioxide.

Section 6 of 7Other mixtures

Mineral water
- a solution of minerals such as calcium, magnesium and sodium dissolved in water.
Evidence
- evaporating drinking water leaves a solid residue that shows it is a mixture.

Section 7 of 7Particle diagrams

Different kinds of atoms bonded together show a compound.
One kind of atom shows an element.
Different particles mixed together but not bonded show a mixture.

Last updated: 12 October 2026