Introduction
Everything around us is made of substances. These substances can be classified into elements, compounds and mixtures. Understanding these concepts helps students learn how matter behaves and how substances are separated in Chemistry.
Elements
An element is a pure substance made up of only one kind of atom. Elements cannot be broken into simpler substances by ordinary chemical methods.
Examples of Elements
- Iron
- Copper
- Gold
- Oxygen
- Hydrogen
Types of Elements
1. Metals
- Shiny in appearance
- Hard substances
- Conduct heat and electricity
- Can be beaten into sheets
Examples: Iron, Copper and Aluminium
2. Non-Metals
- Dull in appearance
- Poor conductors
- Brittle substances
Examples: Sulphur, Oxygen and Carbon
Compounds
A compound is a pure substance formed when two or more elements chemically combine in a fixed ratio.
| Compound | Elements Present |
|---|---|
| Water | Hydrogen + Oxygen |
| Carbon dioxide | Carbon + Oxygen |
| Common Salt | Sodium + Chlorine |
Characteristics of Compounds
- Fixed composition
- New properties formed
- Cannot be separated physically
- Components lose original properties
Mixtures
A mixture is formed when two or more substances combine physically without chemical reaction.
Examples of Mixtures
- Air
- Soil
- Salt and sand
- Sugar in water
Characteristics of Mixtures
- No fixed composition
- Components keep original properties
- Can be separated physically
- No new substance formed
Types of Mixtures
Homogeneous Mixture
A mixture with uniform composition throughout.
Examples: Salt solution and air.
Heterogeneous Mixture
A mixture with non-uniform composition.
Examples: Sand and water, soil.
Difference Between Elements, Compounds and Mixtures
| Element | Compound | Mixture |
|---|---|---|
| One kind of atom | Chemically combined substances | Physically mixed substances |
| Pure substance | Pure substance | Not pure |
| Cannot be broken easily | Can be broken chemically | Can be separated physically |
Methods of Separating Mixtures
Filtration
Used to separate insoluble solids from liquids.
Example: Sand from water.
Evaporation
Used to separate dissolved solids from solutions.
Example: Salt from sea water.
Sieving
Used to separate particles of different sizes.
Magnetic Separation
Uses magnets to separate magnetic substances.
Example: Iron filings from sand.
Solutions
A homogeneous mixture is called a solution.
Components of a Solution
- Solute: Substance dissolved
- Solvent: Substance that dissolves the solute
Example: In salt water, salt is the solute and water is the solvent.
Important Terms
| Term | Meaning |
|---|---|
| Element | One kind of atom |
| Compound | Chemically combined elements |
| Mixture | Physically mixed substances |
| Solute | Substance dissolved |
| Solvent | Substance doing dissolving |
Quick Revision
- Elements contain only one type of atom.
- Compounds are chemically combined substances.
- Mixtures are physically mixed substances.
- Air is a homogeneous mixture.
- Sand and water form a heterogeneous mixture.
Short Questions
- Define element.
- Define compound.
- Define mixture.
- What is a homogeneous mixture?
- Give two examples of compounds.
- Name two methods of separation.
- Differentiate between compound and mixture.
Fill in the Blanks
- Water is a ______.
- Air is a ______ mixture.
- Iron filings can be separated using a ______.
- Salt dissolved in water forms a ______.
Answers
- Compound
- Homogeneous
- Magnet
- Solution
Activity – Magnetic Separation
Materials Needed
- Sand
- Iron filings
- Magnet
Observation
Magnet attracts iron filings.
Conclusion
Magnetic substances can be separated using magnets.
Latest Updates – 2026
Updated: May 18, 2026
- ICSE schools are focusing more on activity-based Chemistry learning.
- Questions related to mixtures and compounds are common in exams.
- Students are encouraged to perform simple separation experiments.
- Visual comparison tables improve understanding of concepts.
FAQ Section
What is an element?
An element is a pure substance made of one kind of atom.
What is a compound?
A compound is formed when elements chemically combine.
What is a mixture?
A mixture is formed by physical combination of substances.
What is a homogeneous mixture?
A mixture with uniform composition throughout.
Can mixtures be separated physically?
Yes, mixtures can be separated using physical methods.