Physical Properties of Metals

Most metals are solid, but mercury and gallium are liquids at room temperature.

1. Malleability: By repeatedly hammering, the wire becomes flat, forming a thin sheet. Hammering can convert metals into sheets, a property called malleability.

Malleability

2. Ductility: It is a special feature of metals that allows them to be stretched into long, thin wires without breaking.

Examples of Ductile Metals:

• Silver is used in jewellery and electronics.
• Gold is used to make fine jewellery because it can be drawn into thin wires.
• Copper is often used in electrical wiring because it can be quickly drawn into wire and conducts electricity well.
• Platinum is also used in jewellery and various industrial applications.

Ductility

3. Electrical conductivity: It is a form of energy that can move or flow through certain materials. Metals like copper, aluminium, and iron are materials through which electricity can flow easily.

Electrical conductivity is a property that tells us how well a material can allow electricity to pass through it. If a material has high electrical conductivity, it means electricity can flow through it very easily. Metals are considered good conductors because they have a lot of free electrons that can move easily.

4. Thermal conductivity: Even when a piece of metal is heated in one place, the whole piece becomes hot. This shows that metals allow heat to flow through them, a property called thermal conductivity.

Thermal conductivity

5. Lustre: Metals usually look shiny, and this shine is called lustre. Different metals have different colours. For example, copper is reddish-brown and gold is yellow. This can help you tell one metal from another. Shine and colour are not just for looks; they can tell us a lot about metal, such as what type it is and what it might be used for.

6. Sonority: Metal produces a ring sound. This property is called the sonority of metals.

7. Density: Metals have high density. Sodium, potassium, and lithium are exceptions, having a lower density than water. The density of lithium is only 0.53 g/cc.

8. Melting Point & Boiling Point: Generally, metals have high melting points and boiling points. Exceptions: Hg, Ga, Na, K.

1. To demonstrate the property of malleability in metals.

• Take a piece of copper or aluminium wire or a small nail.
• Hammer it repeatedly.
• The material flattens and forms a thin sheet.
• This confirms that metals can be shaped into sheets by hammering, demonstrating malleability.

2. Observe the differences in sound produced by various materials when struck or plucked.

• Pluck the string of a musical instrument like a tanpura or veena.
• Ring a bell or hit a steel box with a metal spoon.
• Strike a wooden table or a marble floor with a wooden stick.
• Observe the differences in the sounds produced.
• Metallic objects emit a distinctive ringing sound, demonstrating the sonority of metals.
• Different materials produce different types of sounds when subjected to similar actions.

Uses of metals

• Metals are mostly solids at room temperature; mercury and gallium are exceptions and exist in liquid form.
• Metals have a shining surface called metallic lustre, which may decrease due to oxidation or reaction with gases.
• Malleability allows metals to be beaten into thin sheets (gold and silver are highly malleable), and ductility allows them to be drawn into wires (gold is the most ductile).
• Metals are good conductors of heat and electricity, with silver and copper being excellent conductors.
• Most metals are hard with high melting and boiling points, but alkali metals (sodium, potassium) are soft and low‑melting, and metals are sonorous, producing sound when struck.