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.

Uses of Metals and Nonmetals

• 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.