3. Today we will learn…..
• What is Metal.
• What is Non-metal.
• Physical Properties of Metals and Non-metals.
• Chemical Properties of Metals and Non-
metals.
• Uses of Metals and Non-metals.
4. Activity
Name the material on the basis of Appearance and Hardness.
Object/Material Appearance
(Shiny/Dull)
Hardness
(Very hard /Not very
hard)
Iron Nail
Coal
Sulphur
Copper
6. Metals
• A metal is a material that is typically hard,
opaque, shiny, and has good electrical
and thermal conductivity. Metals are
generally malleable -- they can be hammered
or pressed permanently out of shape without
breaking or cracking as well as fusible --able to
be fused or melted and ductile --able to be
drawn out into a thin wire.
7. Non-metals
• A Non-metal is a material that is dull,softer, it
mostly lacks mettalic attributes. Physically,
nonmetals tend to be highly volatile
(easily vaporized), have low elasticity, and are good
insulators of heat and electricity.
Seventeen elements are generally classified as
nonmetals
• most are gases (hydrogen, helium, nitrogen,
oxygen, fluorine, neon, chlorine, argon, krypton,
xenon and radon)
• one is a liquid (bromine)
• and a few are solids (carbon, phosphorus, sulfur,
selenium, and iodine)
10. Physical Properties of Metals
• Hard and strong - Metals are generally
hard, strong solids. They are strong enough to bear heavy
loads, i.e., they have a high tensile strength.
We generally look for a metal when we need a strong
material. This is because metals are in general hard and
strong. Some examples of metals are magnesium ,
aluminum , iron etc.
Exceptions:
Sodium and potassium are soft solids which can be cut with a
knife, and mercury is a liquid under ordinary conditions.
• Whereas in Non metals ,most of them are gases only few
are solids which are not very hard in nature.
11. Physical Properties of Metals
• Lustrous - They have a lustre, known as
metallic lustre. For example, aluminium, iron,
zinc, copper, silver and gold are all lustrous.
Such metals can be polished too.
• Sonorous-Metals are sonorous. When
struck, they produce a sound called a metallic
sound or metallic clink. Recall the ringing of a
bell or the clink of coins.
12. Physical Properties of Metals
• Malleablity- Metals are malleable. In
other words, they can be beaten or rolled into
sheets.
Aluminium, iron, copper or silver can be
beaten or rolled into thin sheets. Common
examples are the silver foil used to decorate
sweets and aluminium foil used to pack
foodstuff.
13. Physical Properties of Metals
• Ductilty- Metals are ductile, i.e., they are
flexible and can be drawn into wires. For
example, iron, aluminium, copper, silver and
gold can be easily drawn into wires.
Can you draw a wire from a piece of wood or
coal? No, because wood and coal are brittle,
not flexible.
14. Physical Properties of Metals
• Metals are good conductors of heat
- i.e. they allow heat to pass through them easily.
• Due to this property, we use metal utensils in kitchens.
Heat supplied at one place of the utensil is conducted
all over it.
You cannot use a frying pan made of, say, cardboard
because it is a bad conductor of heat. When placed
over fire, cardboard does not distribute the heat all
over the pan. Instead, it starts burning due to the
localised heat.
15. Physical Properties of Metals
• Metals are good conductors of
electricity i.e., they allow an electric current to
pass through them easily. This is why electricity is
transmitted from one point to another through metal
wires, like those of copper or aluminium.
• Silver is the best conductor of electricity; the next
best is copper and then aluminium.
You cannot use nylon or jute ropes for electrical
transmission, as nylon and jute are bad conductors of
electricity.
17. Physical Properties of Non-metals
In contrast to metals, non-metals are not known for
strength. They are :-
1. Usually lustreless (dull) except graphite and iodine,
2. Brittle (if solid)
3. Bad conductors of heat
4. Bad conductors of electricity except graphite
5. Non-sonorous (i.e., they do not produce a metallic clink).
Of the 24 nonmetals known today,
12 are solids (e.g., carbon, silicon, phosphorus, sulphur),
1 is a liquid (bromine), and
11 are gases (e.g., hydrogen, nitrogen, oxygen, fluorine,
chlorine, helium, neon, argon) under ordinary conditions.
20. Chemical Properties of Metals
• Reaction of metals with oxygen:
Metals form their oxides when react with oxygen.
Metal oxides are basic in nature.
Example –
Reaction of Iron metal with oxygen:
4Fe + 3O2 --->2Fe2O3
When iron reacts with moist air, it forms rust. Rust is
iron oxide. Articles made of iron, such as grills,
fencing, etc. are get rusted because of reaction with
moist air.
• Rust is reddish brown in colour and is iron oxide.
• Iron oxide is basic in nature. It turns red litmus blue.
21. Chemical Properties of Metals
Reaction of Magnesium metal with
oxygen:
2Mg + O2 → 2MgO
When magnesium is burnt in air, it forms
magnesium oxide. Burning in air means reaction
with oxygen.
Magnesium oxide forms magnesium hydroxide
with water. Solution of Magnesium oxide turns
red litmus paper blue. This means magnesium
oxide is basic in nature.
22. Chemical Properties of Metals
• Reaction of Metals with water:
Generally, metals form respective hydroxides when they react with
water.
Reaction of sodium metal with water:
Sodium metal vigorously reacts with water and
forms sodium hydroxide along with lot of heat.
Reaction of potassium with water:
2K + 2H2O → 2KOH + H2
Potassium metal vigorously reacts with water and
forms potassium hydroxide along with lot of heat.
23. Chemical Properties of Metals
• Reaction of metals with dilute acid
Metals give hydrogen gas when they react with dilute acid.
Reaction of zinc with dilute acid:
Mg + 2HCl = MgCl2 + H2
Zinc gives hydrogen gas along with zinc chloride when
it reacts with hydrochloric acid.
Similarly, zinc gives hydrogen gas along with zinc
sulphate when it reacts with sulphuric acid.
This method is used to produce hydrogen gas in
laboratory.
Reaction of Aluminium with dilute acid:
2Al(s) + 6HCl(aq) = 2AlCl3(aq) + 3H2(g).
Aluminium gives hydrogen gas along with aluminium chloride
when it reacts with dilute hydrochloric acid.
25. Chemical Properties of Non metals
Reaction of Non-metals with oxygen:
Non-metals forms their oxides when react with oxygen.
Thus,
• Non-metal forms their oxide when reacts with oxygen.
Example -
Reaction of sulphur with oxygen:
• When sulphur is burnt in air, it forms sulphur dioxide.
• Solution of sulphur dioxide turns blue litmus paper red. Sulphur dioxide forms
sulphurous acid when dissolved in water. Thus, sulphur dioxide is basic in nature.
Reaction of carbon with oxygen
• When carbon is burnt in air, it forms carbon dioxide. You can observe that when
coal (carbon) is burnt it forms smoke, which contains carbon dioxide.
• Carbon dioxide is basic in nature. The solution of carbon dioxide in water turns blue
litmus paper red.
•
26. Chemical Properties of Non-metals
• Reaction of Non-metals with water:
Non-metals generally do not react with
water.Rather some non-metals which react with
air vigorously are stored in water.
• Reaction of Non-metals with Dilute
acid:
Generally, non-metals do not react with dilute acid.
27. Use of Metals
Iron is used in making machinery, buildings, car, motorcycle,
ships, bridge, etc.
Copper is used in making electric wires, statue, etc.
Aluminium is used in making kitchen utensils, electric wire,
etc.
Gold is used in making ornaments.
Silver is used in making ornaments.
28. Use of Non-metals
The number of non-metals is very less in comparison to metals
but non-metals are more useful for us. So far only 22 non-metals
are discovered.
We breathe oxygen which is a non-metal. Without oxygen no one
can live.
Sodium chloride (common salt) cannot be formed without
chlorine (a non-metal) which we use to enhance the taste of food.
Without using common salt, food is tasteless.
Nitrogen is used in making fertilizers.
Coal, which carbon, is used as fuel.