LESSON: 4.
Metals and Non metals
Elements:
Elements are chemically simplest substance. A chemical substance is a pure substance
consisting of only one type of atoms.
Note: There are about 118 elements that have been discovered till now.
Classification of elements:
Basically elements are divided into following categories.
1.Metals: Eg: copper, sodium, calcium etc.
2. Non-metals : Eg: oxygen, carbon, silicon, phosphorus etc.
3. Metalloids:
(ii)Reaction of hydrogen with oxygen :
Hydrogen when burns in air it produces popping sound.
1. 2H2 + O2 2H2O
(Hydrogen) (oxygen)
(iii) Reaction of Sulphur:
S + O2 SO2
(Sulphur) (Oxygen) (sulphur dioxide)
Note: Non- Metallic oxide produces acid when dissolved in water.
3. SO2 + H2O H2SO4
(sulphur dioxide) (water) (Sulphuric acid)
Reaction of Metal and Nonmetal with water:
I. Reaction of metals with water:-
Metals:-Generally metals forms Hydroxide when reacts with water which are highly
reactive.
Metal +Water Metal Hydroxide.
(i)Reaction of sodium metal with water-
Sodium and Potassium vigorously react with water to form sodium hydroxide &
Potassium hydroxide along with lot of heat..
i. 2Na + 2H2O 2NaoH + H2 + Heat
(Sodium) (water) (sodium hydroxide)
ii. 2K + 2H2O 2KOH + H2 + Heat
(Potassium) (Water) (Potassium hydroxide)
Reaction of Non-Metal with water;
Non- metal generally do not react with water rather some non metal which react with air
are vigorously stored in water.
The elements which have property of both metal and nonmetal are called metalloids. Eg.
Silicon , germanium etc.
Occurrence of metals :
Metals are mostly found in earth’s crust. Non reactive metals occur in Free State e.g.
gold, silver whereas reactive metals occur in combined state e.g. sodium, calcium etc.
Element or compounds naturally found in earth crust are called MINERALS. The mineral
from which the metal can be extracted are called ORES.
Occurrence of Non metal:
Non metals are the most abundant materials which are present in the universe in free as
well as combined state.
e.g. hydrogen, carbon, sulphur, helium, neon etc.
Gases like Argon(Ag), Helium(He), Neon(Ne) are non reactive and are called noble or
inert gases, they exist in free state.
Physical properties of metals and nonmetals:
The main physical and chemical properties of metals and nonmetals are:
1: Physical state:
Most of the metals are solid at room temperature except mercury which exists in liquid
state.
Nonmetals exist in all the three states i.e. solid, liquid ,gas at room temperature Eg:
Bromine is the liquid nonmetal which exist in liquid state while H2,O2,N2,Cl2,exist in
gaseous state. Solid non metal include silicon, phosphorus.
2: Hardness:
(i)Metals:
Metals are hard in nature except sodium and potassium which are soft in nature that
they can be cut by the help of knife.
(ii)Nonmetals:
They are soft and brittle except diamond which is the hardest substance in nature.
3: Lustre:
(i)Metals:
Glitter or shiny appearance is the property of most of the metals.eg. Gold, silver is
lustrous so they are used in Jewellery.
Nonmetals:
(ii)Almost all nonmetals are dull except graphite and iodine.
4: Malleability:
The property of being beaten or converted into thin sheets without breaking is called
malleability. Eg: gold ,silver, iron, zinc etc.
5: Ductility:
Property of being drawn into wires is called ductility. All metals are ductile while
nonmetals are nonductile. Eg: graphite, iodine, is ductile as they can be drawn into wire.
6: Thermal conductivity:
Metals:
Metals are good conductors of heat and electricity so they are used to make cooking
utensils ,electrical wires and cables.
Note:
• Silver is the best conductor of heat and electricity.
• Immersion rods for heating liquids are made up of metallic substances as metals
are good conductors of heat and electricity.
Nonmetals:
Except graphite, nonmetal are poor conductors of heat and electricity due to this they
are used in making of handles of utensils.
7. Sonority:
Metals:
Property of producing sound is called sonority. Metals are sonorous so they are used for
making musical instruments.
Nonmetals:
Nonmetals are generally non sonorous.
8: Density:
Metals generally have high density except sodium, calcium, magnesium and aluminum.
Note: Lithium is the lightest metal among all other metals.
• Phosphorus is very reactive nonmetal.
Chemical properties of metals and nonmetals:
The main chemical properties of metals and nonmetals are:
1: Reaction of metals with oxygen:
Most metals combine with oxygen to form metal oxide.
Example: 1. Metal + oxygen Metal oxide (basic oxide)
(i)Reaction of magnesium:
2Mg (Magnesium) + O2 2MgO (magnesium oxide)
Magnesium ribbon when it is heated and held over a flame it burns with white dazzling
flame to form magnesium-oxide(MgO)
(ii): Reaction of sodium:
Sodium being a highly reactive with oxygen reacts quickly to form sodium oxide so to
prevent oxidation it is not left in air and kept in kerosene .
4 Na + O2 2Na2O
(Sodium) (Oxygen) (Sodium Oxide)
Note:
Sodium and potassium being highly reactive metal as on exposure to air they get oxidized
therefore they are stored in kerosene.
Corrosion:-
The chemical reaction between a metal and its environment (oxygen and moisture)is
called corrosion. It deteriorates the materials and causes damage to it.
Note:
Corrosion of iron is called Rusting. The brown layer of hydrated iron oxide formed over
surface of iron is called Rust.
4Fe+ 3O2 + xH2O 2Fe2O3.xH2O
(Iron) (Oxygen) (Hydrated Iron Oxide)
2. Reaction of Non-Metals with oxygen:
Generally, nonmetals do not react with oxygen at room temperature, except white
phosphorous which burns in oxygen at ordinary temperature and forms its oxide .It is
therefore stored under water.
Some other non metals also react with oxygen to form non metallic oxides which are
acidic in nature.
Non Metal + Oxygen Acidic Oxide
(i) Reaction of charcoal:
C + O2 CO2
( carbon) ( oxygen) (carbon dioxide)
Note:
When charcoal is burnt in air carbon dioxide gas is evolved. On passing this gas through
lime water it turns milky.
Reaction of Metal and non metal with Acids:
I . Reaction of metals With Acid:-
Metals-Most Metals react with acid to produce salt and hydrogen gas except copper,
silver and gold & platinum.
Metal + Acid Salt + Hydrogen
(I )Reaction of copper with sulphuric acid:
When sulphuric acid is poured in copper, copper sulphate is formed and hydrogen gas
is evolved. On adding iron nails in copper sulphate copper is displaced by iron.
Cu + H2SO4 CuSO4 + H2
(Copper) (sulphuric acid) (copper sulphate) (Hydrogen)
Fe + CuSO4 FeSO4 + Cu
(Iron) (copper sulphate) (Iron sulphate) (copper)
(ii) Mg + 2HCl MgCl2 + H2
(Magnesium) (Hydrochloric acid) (Magnesium Chloride) (Hydrogen)
(iii) Fe + 2HCl FeCl2 + H2
(Iron) (Hydrochloric acid) (Ferrous Chloride) (Hydrogen)
Note:
• Copper, silver & gold do not react with dilute acid.
• Curd and pickle and sour substance are not kept in brass, aluminum or copper
vessel as they are acidic in nature & react with the metallic surface to form some
toxic compounds which may be un healthy for health and can also spoilthe pickles.
II.Reaction of Non Metals with Acids:
Generally non metals do not react with acid. Eg. The nature of the gas can be found by
Potassium is the highly reactive while platinum is least reactive element.
K
Na
Ca
Mg
Al
Zn
Fe
Sn
Pb
H
Cu
Hg
Ag
Au
Pt
Displacement Reaction:-
A reaction in which a more reactive metal displaces the less reactive metal from solution
of its salt.
(i)Reaction of zinc with copper sulphate:
Eg:1. Zn + CuSo4 ZnSo4 + Cu
(Zinc) (Copper sulphate) (zinc Sulphate) (Copper)
Zinc being a more reactive metal displaces the less reactive metal copper from copper
sulphate solution to from zinc sulphate.
(ii) Reaction between Iron and copper sulphate:
Fe + CuSo4 FeSo4 + Cu
(Iron) (Copper sulphate) (Iron Sulphate) (Copper)
Copper being less reactive metal than iron cannot displace iron from its salt solution but
iron can displace copper from its salt solution.
Note:-
A displacement reaction always is accompanied when a element or more reactivity metal
placed in increasing order of reactivity series displaces a less reactive metal from its
compound.
Applications of reactivity series:
1. Iron being at the top of reactivity series being more reactive than gold exist in
combined state where as gold exist in free State .
2. Sodium being more reactive than iron reacts with cold water while iron being less
reactive does not react with it.
Uses of Metals and Non Metals:-
1. Metals:-Some common metals & their uses are
passing it lime water, which turns it milky.
Note: Goldsmith uses acid to clean the jewellery(gold, silver) due to this some amount
of gold and silver dissolves in acid and results in the weight loss of jewellery.
Reactivity Series:-
The reactivity series of metal is a list of common metal arranged in decreasing order of
reactivity.
Copper-
1- For making electrical wires as it is good conductors of heat and electricity.
2- Car radiators & Condensers are made
3- Used for making Coins.
Aluminium-
1- Used for making cooking vessels.
2- Transmission wires & cables are made of Aluminium.
3- Aluminium foils are used for wrapping food items because it is highly malleable
and can be made into foils and being a good conductor it maintains the
temperature of food material.
4- Aluminium powders are used in paints.
Iron:-
1- Pipes, Sinks, tanks, tools , furniture are made of cast iron.
2- Used in constructing of buildings, bridges etc.
3- Stainless steel is used for making utensils as it do not rust & is durable.
Silver:
1. used in jewellery
2. used in photography and electroplating.
Note
1.Silver being costly than copper is not used in making of electrical wires. In addition to
this gold , platinum, silver the noble metal are highly inert in nature and once polished
do not lose their shine .They are therefore used for making jewellery after alloying with
other metals to enhance certain properties.
Mercury:
It is used in thermometers as a thermometric fluid.
Zirconium:
It is used in the preparation of bullet proof alloy of steel as well as in atomic and space
research.
Uses of Non metals:-
1.Silicon:-
• Used in solar cells, transistors & making microchips.
• Used in electronic industries
2.Oxygen:-
• Supports Combustion
• Oxygen stored in cylinders is used by mountains and deep sea-drivers which acts
as artificial oxygen for more meeting requirement of oxygen at higher elevation,
deep under water or at a time of emergency.
3.Sulphur:-
• Used as a fungicide & insecticide.
4.Hydrogen:-
• Used in manufacturing of ammonia
• In extraction of metals.
5.Phosphorous:-
• Used in making matches and fire works
• Phosphate used in making fertilizers.
6.Carbon:
Diamond is used in jewellery while graphite is used in making pencil leads.
7.Nitrogen:
It is used in the preparation of ammonia and in packing of food materials.
8.chlorine:
It is used as bleaching agent , preparation of bleaching powder & gammaxine.
9. Iodine: As antiseptic , iodized salt.
Alloys:
Alloys are the mixtures of two or more metals and non metals. All alloy is usually made
by mixing metals in their molten state.
e.g.
Brass – 65% copper and 35% zinc
Stainless steel – 74%iron, 18% chromium, 8% nickel.
NCERT 