Physical Properties of Non-Metals
- Physical state – Non-metals exists in all three physical state. Carbon, sulphur, phos-phorous etc. are solids. Oxygen, nitrogen, chlorine etc. are gases whereas bromine is a liquid.
- Lustre – Non- metals are non-lustrous substances.
Exception – Diamond, graphite (allotropes of carbon) and iodine are lustrous in appearance.
- Hardness – They are generally soft materials.
Exception – Diamond is the hardest known substance.
- Malleability – Non-metals cannot be beaten into sheets. They are brittle, break into pieces when hammered.
- Ductility – Non-metals cannot be drawn into wires. Thus, they are non-ductile in nature.
- Conduction of heat and electricity – Non-metals are generally bad conductor of heat and electricity.
Exception – Graphite is a good conductor of heat and electricity. It is used for making electrodes.
- Sonority- Non- metals do not produce any sound when hit with a hard object.
- Melting and Boiling point – They generally possess low melting and boiling points.
Exception – Boron, diamond and graphite have high melting points.
♦ Carbon exists in different physical forms such as diamond, graphite etc. are called allotropes.
♦ The most abundant metal in the earth’s crust is aluminium (7%).
♦ The second abundant metal in the earth’s crust is iron (4%).
♦ The most abundant non-metal in the earth’s crust is oxygen (50%).
♦ The second abundant metal in the earth’s crust is silicon (26%).
1. Mercury – Liquid state
2. Alkali metals (Li, Na, K etc.) – Soft, low melting point, low density
3. Zinc, bismuth, arsenic – Non-malleable, non-ductile
4. Gallium, caesium, alkali metals – Low melting point
5. lead, mercury, tungsten – Non conductor of heat
1. Graphite, iodine – Lustrous
2. Diamond – The hardest material
3. Graphite – Good conductor of heat and electricity
4. Boron, diamond, graphite – High melting point
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Chemical Properties of Metals