METAL AND NON METALS

# ELEMENT

Definition

An element is a pure substance which is made up of same kind of atom which differs from their physical and chemical properties.

117 elements are known under which 92 are naturally occurring. Classification of elements

Elements can be classified into 3 types

Metals Non metals Metalloids

CLASSIFICATION OF ELEMENTS

METALS NON METALSMETALLOIDS

COMBINED STATEFREE STATE

GOLD

SILVER

PLATINUM

NA, K, Cain the form of catbonate

, oxides, sulphide

silicon,germanium,

arsenic

COMBINED STATE

FREE STATE

Oxygen, Nitrogen, sulphur, Carbon in the form of graphite, diamond.

Sulphur and carbon in the form of oxides,

carbonates , sulphides

Some abundant elements Aluminium(most) Iron

Most abundant non metal Oxygen

Less reactive metal Gold Silver Platinum

Most reactive metals Sodium Potassium Calcium

Non metal existing in free(native) and combined state Sulphur Carbon

DIFFERENCE BETWEEN MINERAL AND ORE

Mineral oreA mineral is a naturally occurring inorganic substance found deep inside the earth surface

Ore is a mineral from which one or more metals can be extracted economically and profitably.

Examples of ore

Ore of Iron – Hematite ( Fe2O3) ; Magnetite( Fe3O4)

Ore of aluminium – Bauxite( Al2O3.H2O) ; Cryolite (Na3AlF6)

METALLURGY

DEFINITION

Sequence of processes to extract a metal in its pure form from its ore is called metallurgy.

STEPS OF METALLURGY

METALLURGY

STEP 3REFINING OF METAL

STEP 2REDUCTION

STEP 1CONCENTRATION

OF ORE

CONCENTRATION OF ORE

It is the process of removal of impurities from its ore. REDUCTION

It is the process of the reduction of the metal ire to get the metal in its free state. REFINING OF METAL The metal obtained in the second step is impure. Refining is the process of

purification of metal.

Physical properties

Property Metal Non metal

Physical state Are generally solids except mercury(liquid state)

Occur in Solids- carbon,

sulphur, phosphorous. Liquid- bromine Gas- oxygen, nitrogen

Lusture Have shiny appearance Dull appearanceException

Graphite Iodine

Melting & Boiling point High mp.pt and bp.ptExceptionCesium has mp.pt of 28.70c

Low mp.pt & bp.pt

ExceptionCarbon has high mp.pt of 37230c

Hardness Very hard & can withstand high pressure.Exception Na & K are soft and can be easily cut by knife.

Soft

ExceptionDiamond, hardest known substance.

Density High Low

Ductility Metals are ductile

Ductility is defined as the property of metals to be drawn into thin wires.

Most ductile metalsGold & silver.

Non ductile.

Malleability Metals are malleable

Malleability is defined as the property of metals to be drawn into thin sheets on hammering.Most malleable Gold and silver

Non ductile

Conductivity Thermal

conductivity

Electrical conductivity

Property of metals that allows conduction of heat from one region to another.

Property of metals that allows conduction of electricity from one region to another.

Bad conductor of heatException

Graphite

Bad conductors of current

Exception Graphite(form of carbon)

Exception

Lead and mercury are bad conductors

Tensile strength Metals have high tensile strength.

Property of metals due to which it can bear a lot of strain without breaking is called tensile strength.

Do not have tensile strength

Sonorosity Metals are sonorous.

Property of metals to produce a ringing sound when struck is called Sonorosity.

NON SONOROUS

METALLOIDS

There are some metals which show some properties of a metals and non metals. Such elements are called metalloids.

Examples: ARSENIC, GERMANIUM, SILICON

Test yourselfQ Name the metals that are found to occur in the Free State.Q Name the ores of the following metal: Aluminum and IronQ Name the two forms of free carbon that occur in the earth crust.Q Define the following terms: Malleability, ductility, Sonorosity, Tensile strength. Q Give reasons: Copper is used in making boilers Copper is used in making wire nets. Metals are used for making temple bells.Q In the given figure, will the bulb glow? Support your answer with reason

NOBLE

NOBLE METALS

Definition

Those metals that have least reactivity and do not react with air, water, acids and bases are referred to as noble metals.Two noble metals are: GOLD, PLATINUM

Mercury

Q Why noble metals do not get tarnished?

Q silver jewellery when kept in open gets tarnished after some time. Why?

Q Why metals get tarnish after some time when left exposed in air?__________________________________________________________________________________________________________________________________________________________________________________________________________________

Pure gold is soft and its purity is measured in units called CARATS. If gold is 22 carats pure, it means that 22 parts of gold are present in 24 parts of mixture of gold with copper and silver.

Copper and silver are added to make pure gold hard.

Q why gold is alloyed with silver and copper?

Q Calculate the purity of gold in 18 carats of gold

USES OF METALS.

ALUMINIUM

USE PROPERTYIn electrical cables Good conductor

Ductile (can be drawn into thin wires.)

In making cooking utensils Good conductor of electricity.Making aluminum foils Malleable(can be beaten into

thin sheets on hammering) Good conductor of heat

To make alloys like duralumin(for making aircraft)

Light and strong

COPPER

USE PROPERTYIn electrical cables Good conductor

Ductile (can be drawn into thin wires.)

In making cooking utensils Good conductor of electricity.

# GENERAL USES OF METALS

For making electrical fittings, net doors, wires as metals are ductile.

Gold, silver, platinum are used for making jewellery because of its lusture, ductility and malleability.

Are used for making bells, because of the property of sonorosity, which gives ringing sound when struck.

Iron is used for making cooking utensils, water boilers, and chains because of its strength, malleability, ductility and versatility.

Platinum is used in dentistry as it is ductile and least reactive.

Gold and silver is used for high precision electrical contacts in computer as it highly ductile and good conductor of electricity

# ALLOYS

DEFINITION

An alloy is a homogenous mixture of metal and a metal or a metal and a non metal.

Advantage of alloy over metal

Alloys are corrosion resistant. For eg Iron when mixed with chromium and nickel forms stainless steel this is corrosion resistant.

Alloys are hard and have strength. For eg pure gold is soft but when mixed with copper or silver becomes hard.

Alloys are chemically resistant.

Have low melting point. For eg SOLDER alloy of lead and tin have low melting point than the metal.

Uses of Non Metals

Nitrogen For making fertilizers Help in making proteins.

Phosphorous In match industry As fertilizers

Iodine As antisepticSulphur In fire crackers

In making gun powder

SEE TABLE 3 FROM PAGE NO 40

In preparation of sulphuric acid.

Oxygen For survival

Carbon Used for making jewellery in the form diamond. Diamond is used for cutting and grinding tool. Graphite is used for making batteries Graphite is used in pencils.

Test yourself

Q What is an alloy?Q Why alloy is generally preferred over metals?Q Complete the table:

Use Name of the alloy composition

In making surgical instruments

For making permanent magnets

For making coins and medals.

Q Name two alloys of each:a) Copperb) Iron

Q Identify the element:

a) The element ‘X’ is used in making of machine parts. It is malleable, ductile and has high tensile strength.

b) Also give one alloy of the above element.