Category : 8th Class
Materials - Metals and Non-Metals
· Materials can be classified into metals and non-metals.
· Metals can be distinguished from non-metals on the basis of their physical and chemical properties.
· Physical properties of metals
§ Metals are hard, lustrous, malleable, ductile, sonorous and good conductors of heat and electricity. Iron, copper, aluminum, calcium and magnesium are some examples of the metals.
· Metals are generally hard but the metals like sodium and potassium are soft and can be cut with a knife. Similarly, mercury is the only metal which is found in liquid state at room temperature.
· Chemical properties of metals
§ Metals on burning in the presence of oxygen, produces metal oxides which are basic in nature.
§ Metals on reaction with water produce metal hydroxides and hydrogen gas.
§ Metals on reaction with acids produce metal salts and hydrogen gas.
§ Some metals react with bases to produce hydrogen gas.
§ More reactive metals displace less reactive metals from their compounds in aqueous solutions. This type of reaction is called displacement reaction.
· Physical properties of non-metals
§ Non -metals are soft and dull in appearance, break down into powdery mass on tapping with hammer, are not sonorous and are poor conductors of heat and electricity.
· Diamond which is the hardest known element on the earth is a non-metal.
· Chemical properties of non-metals
§ Non-metals react with oxygen to produce non- metallic oxides which are acidic in nature.
§ Non-metals generally do not react with water.
§ Non-metals do not react with acids.
· Metals and non-metals are used widely in everyday life.
You need to login to perform this action.
You will be redirected in
3 sec