Submitted by ,

Balendu Kumar

viii a

Roll No: 43

NON-METALS

METALS AND

Elements can be classified as :

METALS NON METALS

on the basis of their properties…

INTRODUCTION

A metal is a chemical element that is a good conductor of

both electricity and heat and forms cations and ionic bonds

with non-metals. In chemistry, a metal is an element, compound, or alloy characterized by high electrical

conductivity. In a metal, atoms readily lose electrons to form positive ions (cations). Those ions are surrounded by

delocalized electrons, which are responsible for the conductivity.

SilverRhenium Iridium

Physical properties of metals :-

• Metals are solids. (except mercury)

• Metals are hard. (except Lithium, Potassium, Sodium)

• Metals have metallic lustre. (shine)

• Metals are malleable. (can be beaten into thin sheets)

• Metals are ductile. (can be drawn into wires)

• Metals have high melting points. (Gallium and Ceasium have low melting points. They melt in the palm of the hand)

• Metals have high boiling points.

• Metals are good conductors of heat. ( Best conductors are silver and copper. Poor conductors are Lead and Mercury)

• Metals are good conductors of electricity. ( Best conductors are Silver and Copper)

• Metals are sonorus. (produce sound when beaten)

A chemical element that is not a metal , for example ; carbon or oxygen . Non-metals are solids and gases and are not good conductors of heat and electricity..

Chemical elements that form negative ions, have acidic oxides, and are generally poor conductors of heat and electricity are called non metals..

Rubidium BoronPhosphorus

Physical properties of non metals :-

• Non metals may be solids, liquids or gases. (Solids – Carbon, Sulphur, Phosphorus etc. Liquid – Bromine, Gases – Oxygen, Hydrogen, Nitrogen etc.)

• Non metals are soft. (except diamond which is the hardest natural substance)

• Non metals do not have lustre.( except iodine crystals)

• Non metals are not malleable.

• Non metals are not ductile.

• Non metals which are solids and liquids have low melting points.

• Non metals which are solids and liquids have low boiling points.

• Non metals are bad conductors of heat.

• Non metals are bad conductors of electricity. (except graphite)

• Non metals are not sonorus.

Metals and non metals differ from

each other in their chemical

properties also. Let us compare

the chemical properties of metals

with those of non metals. They are

as follows-

1.)Reaction with oxygen

2.)Reaction with water

3.)Reaction with acids

4.)Displacement Reaction

5.)Reaction with Bases

Chemical properties of metals and non – metals :-

a) Reaction with oxygen :-Metals react with oxygen to form metallic oxides. These oxides are

basic oxides because they react with water to form bases.

Eg. Magnesium burns in air to form magnesium oxide. Magnesium

reacts with water to form magnesium hydroxide.

2 Mg + O2 2 MgO

MgO + H2O Mg(OH)2

Non metals react with oxygen to form non metallic oxides. These

oxides are acidic oxides because they react with water to form

acids.

Eg. Sulphur burns in air to form sulphur dioxide. Sulphur dioxide

reacts with water to form sulphurous acid.

S + O2 SO2

SO2 + H2O H2SO3

b) Reaction with water :-

Metals react with water to form metal hydroxides and hydrogen.

Eg. Sodium reacts with water to form sodium hydroxide and

hydrogen.

2 Na + 2 H2O 2 Na OH + H2

Magnesium reacts with water to form magnesium hydroxide and

hydrogen.

Mg + H2O Mg(OH)2 + H2

Non metals do not react with water.

b) Reaction with water :-

Metals react with acids to form metallic salts and hydrogen.

Eg. Zinc reacts with dilute hydrochloric acid to form zinc chloride

and hydrogen.

Zn + 2 HCl ZnCl2 + H2

Most non metals do not react with acids. Some non metals like sulphur reacts with concentrated nitric acid to form sulphur dioxide, nitrogen dioxide and water.

S + 4 HNO3 SO2 + 4 NO2 +2 H2O

d) Displacement Reaction :-

A more reactive metal displaces a less reactive metal from its salt solution. (Displacement reaction)

Magnesium displaces copper from copper sulphate solution.

Mg + CuSO4 MgSO4 + Cu

Zinc displaces copper from copper sulphate solution.

Zn + CuSO4 ZnSO4 + Cu

Iron displaces copper from copper sulphate solution

Fe + CuSO4 FeSO4 + Cu

after 15 – 20 minutes

Metals have been an integral part of our

daily life since ancient times. They have

played an important part in the

development of various civilisations.Iron

is the most widely used metal. It is used

for making cooking vessels,water boilers

etc.Aluminium being a very light metal, is

used for making aircraft bodies .Silver is

used for making jewellery,decoration

pieces,tableware etc.Gold and silver wires

are used for high electrical contacts in

computers.

Some of common uses are-

1.)Iodine is used as antiseptic.

2.)Oxygen is essential for all human beings.

3.)Sulphur is used for making fire crackers.

4.)Phosphorous is used in match box industry and fertilizers.