Materials: Metals and Non-Metals 1

Introduction

The metals can be distinguished from the non-metals on the basis of their chemical and physical properties.
The property of metals by which they can be beaten into thin sheets is known as malleability.
The property of metal by which it can be drawn into wires is known as ductility.
The metals are normally hard, malleable, lustrous, ductile, sonorous, and good conductors of heat and electricity. E.g. iron, copper, calcium, aluminum, magnesium, etc.

The materials, which are not sonorous and are poor conductors of heat and electricity, are known as non-metals. E.g. sulphur, carbon, oxygen, phosphorus, etc.
Some metals, such as sodium and potassium are soft and can be cut with a knife.
Mercury is the only metal, which remains in liquid state at room temperature.
When sulphur dioxide is dissolved in water, sulphurous acid is formed. Illustration - Sulphur dioxide (SO₂) + Water (H₂O) → Sulphurous acid (H₂SO₃).
Oxides of non-metals are acidic in nature.
The sulphurous acid changes blue litmus paper red.
Phosphorus is a very reactive non-metal and it catches fire whenever exposed to air.
To prevent the contact of phosphorus with atmospheric oxygen, Phosphorus is stored in water.
On burning, metals easily react with oxygen and produce metal oxides, these are basic in nature.
Non-metals react with oxygen and produce non- metallic oxides; these are acidic in nature.
Some metals react with water and produce metal hydroxides and hydrogen gas.
Nonmetals normally do not react with water.
Metals also react with acids and produce hydrogen gas and metal salts.
Non-metals normally do not react with acids.

Metals are used in making machinery, airplanes, automobiles, trains, satellites, industrial gadgets, cooking utensils, water boilers, etc.
Non-metals are used in fertilizers to improve the growth of plants.
Non-metal are used in water purification.
Non-metals are used in crackers.