Class 10 Science Study Material
Chapter 3: Metals and Non-Metals
Section 2: Physical Properties of Metals
CBSE Class 10 Exam-Oriented Notes
📄 Official Study Companion PDF:
Download Chapter 3 Notes PDFLearning Objectives
After studying this section, you should be able to:
- Define physical properties of metals.
- Explain why metals are useful in everyday life.
- Differentiate between metals and non-metals based on physical properties.
- Write reasons for important properties in board examinations.
- Solve MCQs, assertion-reason, and competency-based questions.
What are Physical Properties?
Physical properties are those characteristics of a substance that can be observed or measured without changing its chemical composition.
Examples:
- Colour
- Shine
- Hardness
- Density
- Malleability
- Ductility
- Conductivity
- Melting point
- Boiling point
- Sonority
1. Lustrous Nature
Definition
Metals have a shiny surface, known as lustre.
Why?
Their free electrons reflect light, making the surface shiny.
Examples
- Gold
- Silver
- Copper
- Aluminium
Applications
- Jewellery
- Mirrors
- Decorative articles
- Coins
Important Point
Freshly cut sodium also shines but quickly loses its shine because it reacts with oxygen.
2. Malleability
Definition
Malleability is the property by which metals can be beaten into thin sheets.
Examples
- Gold
- Silver
- Aluminium
- Copper
Uses
- Aluminium foil
- Cooking utensils
- Roofing sheets
- Car bodies
Important Fact
Gold is the most malleable metal.
3. Ductility
Definition
Ductility is the ability of metals to be drawn into thin wires.
Examples
- Copper
- Aluminium
- Silver
- Gold
Uses
- Electrical wires
- Telephone cables
- Power transmission lines
Important Fact
Gold is also the most ductile metal.
Difference Between Malleability and Ductility
| Malleability | Ductility |
|---|---|
| Can be beaten into sheets | Can be drawn into wires |
| Used for foil and utensils | Used for electrical wiring |
4. Good Conductors of Heat
Definition
Most metals allow heat to pass through them easily.
Examples
- Silver (Best conductor)
- Copper
- Aluminium
Applications
- Cooking utensils
- Pressure cookers
- Heat exchangers
Important Note
Silver conducts heat best but is expensive, so aluminium and copper are commonly used.
5. Good Conductors of Electricity
Definition
Metals allow electric current to pass through them easily.
Why?
Metals contain free-moving electrons.
Examples
- Silver
- Copper
- Aluminium
Applications
- Electric wires
- Motors
- Transformers
- Electrical appliances
Important Point
Copper and aluminium are widely used because they are cheaper than silver.
6. Hardness
Most metals are hard.
Examples
- Iron
- Tungsten
- Titanium
Exceptions
- Sodium
- Potassium
These can be cut easily with a knife.
7. High Density
Most metals have high density.
Examples
- Iron
- Copper
- Lead
Uses
Heavy machinery
Construction
Bridges
Buildings
8. High Melting and Boiling Points
Most metals have very high melting and boiling points.
Examples
Iron – High melting point
Tungsten – Highest melting point among common metals
Uses
Electric bulbs (filament)
Furnaces
Industrial equipment
9. Sonorous Nature
Definition
Metals produce a ringing sound when struck.
This property is called:
Sonority
Applications
- School bells
- Temple bells
- Musical instruments
10. Strength
Most metals possess high tensile strength.
Examples
- Iron
- Steel
- Titanium
Uses
- Buildings
- Bridges
- Railway tracks
- Machinery
Exceptions of Metals
Not all metals follow every property.
| Metal | Exception |
|---|---|
| Mercury | Liquid at room temperature |
| Sodium | Soft metal |
| Potassium | Soft metal |
| Gallium | Melts in hand |
| Lead | Soft and poor conductor compared to other metals |
Why Metals Conduct Heat and Electricity
Metals contain free electrons.
These electrons move freely throughout the metal.
As a result,
- Electricity flows easily.
- Heat transfers quickly.
Summary Table
| Property | Meaning | Example | Use |
|---|---|---|---|
| Lustrous | Shiny | Gold | Jewellery |
| Malleable | Can be beaten into sheets | Aluminium | Foil |
| Ductile | Can be drawn into wires | Copper | Electrical wires |
| Conductive | Conducts heat & electricity | Silver | Electrical equipment |
| Sonorous | Produces sound | Iron | Bells |
| Hard | Difficult to break | Iron | Construction |
| High Melting Point | Melts at high temperature | Tungsten | Bulbs |
Important CBSE Points to Remember
- ✅ Gold is the most malleable metal.
- ✅ Gold is the most ductile metal.
- ✅ Silver is the best conductor of heat and electricity.
- ✅ Copper is widely used for electrical wiring.
- ✅ Aluminium is used for cooking utensils due to its good conductivity and low weight.
- ✅ Mercury is the only liquid metal at room temperature.
- ✅ Sodium and potassium are soft metals.
- ✅ Metals are generally hard, lustrous, sonorous, malleable, and ductile.
Frequently Asked Board Questions
- Define malleability with an example.
- Define ductility with an example.
- Why are metals good conductors of electricity?
- Why is copper used in electrical wiring?
- Why is aluminium used to make cooking utensils?
- Name the metal that is liquid at room temperature.
- Name the soft metals that can be cut with a knife.
- Explain the term sonorous.
- Differentiate between malleability and ductility.
- State three physical properties of metals.
Quick Revision (1-Minute Recap)
- • Lustrous → Shiny
- • Malleable → Beaten into sheets
- • Ductile → Drawn into wires
- • Conductors → Heat and electricity
- • Sonorous → Produces ringing sound
- • Hard → Strong and durable
- • High melting point → Used in industries
- • Mercury → Liquid metal
- • Gold → Most malleable and ductile
- • Silver → Best conductor of heat and electricity