MATERIALS METALS AND NON METALS
MATERIALS METALS AND NON METALS
Materials around us can be classified as metals and non-metals based on their physical and chemical properties
(Note:- Materials which show intermediate properties of metals and nonmetals are known as metalloids
Eg:- boron, silicon, germanium)
PHYSICAL PROPERTIES OF METALS
1)LUSTRE
Lustrous means something that shines. Metallic lustre is a property of the metal to have a shining surface
(All the metals have lustre property. Gold platinum and silver are comparatively more lustrous than other metals)
2) HARDNESS
Generally, metals have high density and they are solid at room temperature so they are hard it is not easy to break or change the shape of metals
(Most of the metals are hard but sodium and potassium are soft metals that can be cut with a knife )
3)MALLEABILITY
The property of metal by which it can be beaten into thin sheets is called malleability
(Aluminum foil used to wrap food material is a good example of the malleability of metals)
4)DUCTILITY
The property of metal by which it can be drawn into thin wires is called ductility
(Eg:- copper wire and aluminium wire are used as electric wires)
5)CONDUCTIVITY
Metals are generally good conductors of heat and electric current (they allow heat and electricity to pass through them)
(Eg:- aluminium is used for making cooking utensils. Copper and aluminium are used to make electrical connection wires)
6)SONORITY
The property of a metal by which it can produce a ringing sound when struck is called sonority
(Metals are used to make bells)
Metals usually show the properties mentioned above.
Eg:- iron, aluminium, copper, zinc, sodium, calcium etc.
Non-metals generally do not show these properties such as lustrous, sonorous, malleable, ductile, conductivity etc. But they display varieties of colours
Eg:-carbon, nitrogen, phosphorus, chlorine, oxygen, hydrogen etc.
EXCEPTIONS IN METAL AND NON METALS
1. All the metals except mercury are solid at room temperature
2. Iodine is a lustrous non metal
3. Diamond and graphite are forms of carbon(non-metal), but diamond is the hardest natural substance known and graphite is a conductor of electricity
4. Sodium, lithium and potassium are soft metals that can be cut with a knife
USES OF METALS AND NON METALS
Metals have a lot of uses in our daily life making cooking utensils, electrical wires, making machinery etc.
Non-metals are used in the preparation of fertilizers(nitrogen, hydrogen ), used in antiseptics(iodine), essential for leaving beings for breathing (oxygen ) and used in crackers (phosphorus )
