Metals and non-metals · धातु और अधातु
A free Chemistry lesson for Class 8 children.
Metals are hard, shiny, and good conductors of heat and electricity. They are malleable, so they can be beaten into sheets, and ductile, so they can be drawn into wires.
Non-metals like sulphur, carbon and phosphorus are dull, brittle and poor conductors.
Metals react with oxygen to form basic oxides. Magnesium oxide turns red litmus blue. Non-metal oxides, like sulphur dioxide, are acidic.
Sodium and potassium react violently with water, so they are kept in kerosene. Iron reacts slowly with water and air to form rust.
A more reactive metal displaces a less reactive one from its salt solution: iron displaces copper from copper sulphate.
Metals are used for wires, machines and vehicles. Non-metals are used too: oxygen for breathing, nitrogen in fertilisers, chlorine to purify water.