Physical Properties of Non-Metals

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Physical Properties of Metals

Non-metals

1. 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.
2.  Lustre – Non- metals are non-lustrous substances.           
   Exception – Diamond, graphite (allotropes of carbon) and iodine are lustrous in appearance.
3. Hardness – They are generally soft materials.
   Exception – Diamond is the hardest known substance.
4. Malleability – Non-metals cannot be beaten into sheets. They are brittle, break into pieces when hammered.
5. Ductility – Non-metals cannot be drawn into wires. Thus, they are non-ductile in nature.
6. 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.
7. Sonority- Non- metals do not produce any sound when hit with a hard object.
8. 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%).

Common Exceptions
Metals          
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

Non-metals    
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