Properties of metals and non-metals
Every use of a metal starts with a property
1. General properties: mass, radius and metallic property
2. Foil or powder?
You can hammer aluminum into thin kitchen foil. Hit a lump of sulphur, and it breaks into powder.
Pick the right answer
Predict: which property lets aluminum become foil?
- A. It conducts electricity
- B. It is malleable: it can be hammered into sheets
- C. It is shiny
الشرح
Aluminum becomes foil because it is malleable: it can be hammered into thin sheets without breaking. Metals are usually malleable, while a solid non-metal such as sulphur is brittle.
3. Metals vs non-metals
| Property | Most metals | Most non-metals |
|---|---|---|
| Look | shiny | dull |
| Heat and electricity | good conductors | poor conductors |
| Hammering | malleable (sheets) and ductile (wires) | brittle when solid |
| State at room temperature | solid, high melting points | many are gases, e.g. O₂, N₂ |
Notice the word most. Each row has exceptions, as you'll see next.
4. Property → use
Chemists choose a metal for a job because of a property.
| Metal: property | Use |
|---|---|
| Copper: good conductor of electricity | Electric cables |
| Aluminum: malleable | Kitchen foil |
| Gold: shiny | Jewellery |
True or false?
It conducts electricity, so it must be a metal.
الشرح
Judge by several properties (look, conducting, hammering, state), not by one.
5. Apply it
Pick the right answer
Heating coils need a metal that can be drawn into long, thin wires. Which property is that?
- A. Ductile
- B. Malleable
- C. Good conductor of heat
- D. Shiny
الشرح
Being drawn into long, thin wires is called ductile. Malleable is about being hammered into sheets; conducting heat and being shiny are other properties.
Sort into groups
Metal or non-metal? Use all the clues.
A shiny solid that conducts electricity and is hammered into sheetsA yellow solid that breaks into powder and does not conductGraphite: a black solid that conducts electricityMercury: a shiny liquid that conducts electricityA colourless gas, a poor conductor
6. Summary
- Most metals are shiny, good conductors of heat and electricity, malleable and ductile, with high melting points.
- Most non-metals are dull, poor conductors and brittle when solid; many are gases.
- A metal is chosen for a use because of a property, e.g. copper in electric cables.
Match the pairs
Match each property to the use it explains.
- Good conductor of electricity
- Malleable
- Ductile
Next in Chapter 1: some metals are too brittle to use pure. Watch for the reason each time.
Can you explain why 'it conducts electricity, so it's a metal' can be wrong?