Metals & non metals class 10 science...

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  METALS & NON- METALS 

Metals:

• Metals are those elements which possess lustre when freshly cut and are malleable and ductile and good conductor of heat & electricity.

• Metals are those element which lose electrons and form positive ions. 

 Malleable: It means which can be beaten with hammer to form thin sheets without breaking.

Ductile: It means which can be drawn into wires.

Importance of Metals:

Metals are of great importance in our everyday life. They are used for a large number of purposes.
• Utensils used at home are made of metals.
• Metals are used in the construction of buildings and bridges.
• In making of almost all types of machine parts.
• In the manufacture of automobiles, aeroplanes, ships, trains etc. 
• Silver & gold are used in making of jewellery.

Non-Metals:

• Non metals are those elements which do not possess lustre & are neither good conductor of heat& Electricity nor malleable & ductile but are brittle.

• Non-metals are those elements which gain electrons & form negative ions

Brittle:  It means which breaks into pieces on hammering or stre

Importance of non metals:

Though the number of non- metals is small as compared to metals, yet they play a very important role in our everyday life.

• carbon:  It is one of the most important non-metal. This is because all the life on this earth is based on carbon compounds for ex. Proteins, oils, fats,& vitamins.
• Oxygen: It is another non metal which is equally important for existence of life & combustion processes.
• Nitrogen: It is an inert gaseous non- metal. It's presence in the air reduces the rate of combustion.
• Sulphur: It is another non- metal which is present in many of the substances found in plants & animals.

PHYSICAL PROPERTIES OF METALS:

• METALLIC LUSTRE:  Metals in the the pure state possess lustre having a shining surface. Metals such as Aluminium & magnesium appear white, while copper is reddish brown.

• HARDNESS:  Metals are generally hard. The hardness varies from metal to metal. 

• MALLEABILITY:  Metals are generally malleable they can be beaten into thin sheets. 

• DUCTILITY:  Metals are generally ductile, they can be drawn into wires.
       Gold is the most ductile metal.

• THERMAL CONDUCTIVITY:  Metals are good conductor of heat & possess high melting points.

• ELECTRICAL CONDUCTIVITY:  Metals are good conductor of electricity, they allow Electricity to pass through them easily.


PHYSICAL PROPERTIES OF NON-METALS:

• NO LUSTRE: Non-metals do not possess any lustre. Only iodine has lustre, yet it is non metal.

• NON-MALLEABILITY& NON-DUCTILITY:  In solid state, non metals are neither malleable nor ductile.

• BRITTLENESS:  Non metals are soft & brittle they break into pieces when hammered. For ex. sulphur & phosphorus, on hammering, break & crumble.

• POOR CONDUCTORS OF HEAT & ELECTRICITY:
Non- metals are generally poor conductors of heat & electricity. Graphite is an exception, as it is good conductor of electricity.

• NON-SONOROUS:  Metals are non sonorous they do not produce any sound when hit with a hard object.

• NON METALS HAVE LOW DENSITY: Non metals are light elements. For ex. The density of phosphorus is 1.8 g/cm.

• LOW MELTING POINT & BOILING POINT: Diamond, graphite & boron are the exceptions as these are the non-metals with high melting points.
• METALS HAVE LOW TENSILE STRENGTH:  Metals are easily broken.

• METALS MAY BE SOLIDS, LIQUIDS OR GASES AT ROOM TEMPERATURE:  For ex.. carbon, sulphur, phosphorus & iodine are solid non-metals, bromine is a liquid non-metal which are hydrogen, oxygen, nitrogen & chlorine are gaseous non-metals.
 






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