Materials Metals and Non Metals

CBSE Class: 08
Revision Notes
Chapter – 4
Materials: Metals and Non-Metals

Metals are strong and durable. Thus metals are used so widely for making almost everything
Example: Metals are used in making machinery, automobiles, aeroplanes, buildings, trains, satellites, gadgets, cooking utensils, water boilers...etc.

Physical Properties of Metals

The metal base in an electric iron is for conducting heat, not electricity.
Metals are very good conductors of heat. Cooking utensils, irons, heaters, etc. are all made of metals which are good conductors of heat.
Metals can be easily shaped into wires. This property of metals is called ductility.
Metals can be easily shaped into thin flat sheets. This characteristic of metals is called malleability.
Metals make a sound when struck with hard objects. Metals can be polished to a shiny appearance.

Chemical Properties of Metals

metals react with oxygen to produce metal oxides which are basic in nature. Non-metals react with oxygen to produce non- metallic oxides which are acidic in nature.
Some metals react with water to produce metal hydroxides and hydrogen gas. Generally, non- metals do not react with water.
Metals react with acids and produce metal salts and hydrogen gas. Generally, non-metals do not react with acids.
Some metals react with bases to produce hydrogen gas.
More reactive metals displace less reactive metals from their compounds in aqueous solutions

Physical Properties of Non-metals

Non-metals are non-lustrous, non-malleable and not ductile, except for carbon fibres, which are ductile.
Non-metals are not sonorous. They do not produce any sound when hit..
Non-metals do not conduct heat and electricity except for graphite

.Chemical Properties of Non-metals·

Non-metals react with oxygen to form their oxides. Non-metal oxides are acidic or neutral in nature.
In general non-metals do not react with water though they may be very reactive in air.
Non-metals do not react with acids