Physical properties of metals and non-metals
Metals are usually lustrous, malleable, ductile, sonorous and good conductors. Non-metals are usually dull, brittle and poor conductors. Learn the exceptions well.
Metals and non-metals compared
| Property | Metals | Non-metals |
|---|---|---|
| Lustre (shine) | Metallic lustre | No lustre: dull |
| Malleability and ductility | Malleable and ductile | Neither; solids such as coal (carbon) and sulphur are brittle |
| Hardness | Usually hard | Usually soft compared with metals |
| State at room temperature | Solids (mercury is a liquid) | Solids, liquids or gases (bromine is a liquid) |
| Sound | Sonorous | Not sonorous |
| Density | Usually high | Usually low |
| Heat and electricity | Good conductors | Poor conductors |
Exceptions to remember
| Exception | Why it is special |
|---|---|
| Mercury | The only metal that is liquid at room temperature |
| Bromine | The only non-metal that is liquid at room temperature |
| Sodium | A metal so soft that it can be cut with a knife, like wax |
| Gallium | A metal that melts if you hold it on your palm |
| Graphite and iodine | Non-metals with a metallic lustre |
| Graphite | The non-metal that is a good conductor of electricity |
| Diamond | A form of carbon that conducts heat better than copper, but does not conduct electricity |
| Gold, silver, platinum, copper | Found free in nature, because they react very little |
Activity: compare iron, copper and aluminium
- 1Collect small samples of iron (a nail), copper (a piece of wire) and aluminium (a strip of foil or an old vessel).
- 2Note the colour and shine of each.Iron is grey, copper reddish-brown and aluminium silvery white; old surfaces may look dull
- 3★Rub each surface with sandpaper and compare.The rubbed surfaces shine much more. A clean metal surface has metallic lustre; the dull layer was a coating formed by air
- 4Tap each with a spoon and try bending thin pieces.They ring (sonorous) and bend without breaking
★ key step
Uses that come from these properties
| Use | Property used | Metals |
|---|---|---|
| Cooking vessels and frying pans | Good conductors of heat | Aluminium, copper, iron, stainless steel |
| Electric wires | Ductile and good conductors of electricity | Copper, aluminium |
| Sheets for building and containers | Malleable | Iron, aluminium |
| Jewellery | Lustrous, malleable and hardly react | Gold, silver, platinum |
| Steel ropes for cranes and bridges | Strong | Steel |
| Cells and batteries | Take part in the cell reactions | Zinc, lead, mercury, lithium |
The thin silver varq on sweets and fine gold jewellery show how malleable these metals are. Copper is used for the electric wiring in homes because it is ductile and conducts electricity well.
2 marks: “(i) Name the metal and the non-metal that are liquids at room temperature. (ii) Name a non-metal that has lustre.” (i) Mercury and bromine. (ii) Iodine (or graphite).
2 marks: “Why are copper and aluminium used to make electric wires?” They are ductile, so they can be drawn into thin wires, and they are good conductors of electricity.
3 marks: “Give four physical properties in which metals differ from non-metals.” Lustre: metals shine, non-metals are dull. Malleability and ductility: metals have them, non-metals are brittle. Conduction: metals are good conductors, non-metals poor (except graphite). Sound: metals are sonorous, non-metals are not.
Metals shine, flatten, stretch, ring and conduct. Mercury and bromine are the liquid rebels.