NCERT Solutions of Materials : Metals and Non-Metals Class 8
<< Solution: Exercise of NCERT BookChemical Properties of Metals and Non-metals >>

Materials : Metal and Non-metals

Introduction of Metals and Non-metals

Materials are classified into two types metals and non-metals; on the basis of their properties. For example aluminium, copper, iron, silver, etc. are metals. Sulphur, carbon, nitrogen, oxygen, etc. are non-metals.

Physical properties of Metals and Non-metals

Hardness

Metals Metals are generally hard. For example; iron, copper, silver, gold, aluminium, etc. But some metals, such as mercury, sodium, calcium, etc. are not hard.

Non-metals Non-metals are not hard. For example phosphorous, sulphur, etc. Diamond is exception, which is a type of non-metal, coal. Diamond is the hardest naturally occurring material.

Appearance:

Metals Metals are shiny in appearance. For example iron, gold, silver, copper, etc.

Non-metals Non-metals are dull in appearance. For example coal.

Sonorous:

Metals - Metals produce ringing sound when beaten, i.e. metals are sonorous. This is the reason that bells are made of metal.

Non-metals Non-metals do not produce ringing sound when beaten. And thus, non-metals are non-sonorous.

Ductility:

Metals Metals are ductile in nature. This means metals can be beaten into thin sheets. For example thin sheets of iron are used in making the body of vehicle, ship, roof of thatched house, etc.

Non-metals Non metals are not ductile. When non-metal is beaten it broken into pieces, thus metals are called brittle. For example when a lump of coal is beaten using a hammer, it is broken into pieces.

Malleability:

Metals: Metals can be drawn into wire. This property of metal is called malleability and thus metals are malleable. For example electric wires are made of metals, such as aluminium, copper, etc.

Non-metals: Non-metals are brittle and thus cannot be drawn into wire.

Conductor:

Metals: Metals are good conductor of electricity and heat. This is the cause that electric wire and kitchen utensils are made of metals.

Non-metals: Non-metals do not conduct electricity or heat and they are bad conductor. However, graphite; which is a non-metal; is an exception as it conducts electricity.

Thus, materials which are hard, sonorous, good conductors of electricity and heat, malleable, ductile and have shiny appearance are called metals.
And materials which are not hard, non-sonorous, bad conductors, brittle and dull in appearance are called non-metals.

NCERT Solutions of Materials : Metals and Non-Metals Class 8
<< Solution: Exercise of NCERT BookChemical Properties of Metals and Non-metals >>

Materials : Metal and Non-metals will be available online in PDF book form soon. The solutions are absolutely Free. Soon you will be able to download the solutions.