Metal and Non Metals

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

FREE STATE GOLD SILVER

METALLOIDS

COMBINED STATE

silicon, germanium, arsenic

NA, K, Ca in the form of catbonate , oxides, sulphide

PLATINUM

 Some abundant elements • Aluminium(most) • Iron  Most abundant non metal • Oxygen  Less reactive metal • Gold • Silver • Platinum  Most reactive metals • Sodium • Potassium • Calcium

NON METALS

FREE STATE

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

COMBINED STATE

Sulphur and carbon in the form of oxides, carbonates , sulphides

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

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DIFFERENCE BETWEEN MINERAL AND ORE Mineral A mineral is a naturally occurring inorganic substance found deep inside the earth surface

ore 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

STEP 1 CONCENTRATION OF ORE

STEP 2 REDUCTION

METALLURGY

• • • •

STEP 3 REFINING OF METAL

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)

Lusture

Have shiny appearance

Melting & Boiling point

High mp.pt and bp.pt Exception Cesium has mp.pt of 28.70c

Occur in • Solids- carbon, sulphur, phosphorous. • Liquid- bromine • Gas- oxygen, nitrogen Dull appearance Exception • Graphite • Iodine Low mp.pt & bp.pt

Hardness

Density

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

Ductility

Metals are ductile

Exception Carbon has high mp.pt of 37230c Soft Exception Diamond, hardest known substance. Low Non ductile.

Ductility is defined as the property of metals to be drawn into thin wires. Most ductile metals Gold & silver.

Malleability

Metals are malleable

Non ductile

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

Conductivity • Thermal conductivity •

Electrical conductivity

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

Bad conductor of heat Exception Graphite

Property of metals that allows conduction of Bad conductors of current electricity from one region to another. Exception

Graphite(form of carbon) Exception Lead and mercury are bad conductors

Tensile strength

Metals have high tensile strength.

Do not have tensile strength

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

Sonorosity

Metals are sonorous.

NON SONOROUS

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

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 yourself Q Name the metals that are found to occur in the Free State. Q Name the ores of the following metal: Aluminum and Iron Q 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

Mercury

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 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 In electrical cables

In making cooking utensils Making aluminum foils

To make alloys like duralumin(for making aircraft)

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• • • • • •

PROPERTY Good conductor Ductile (can be drawn into thin wires.) Good conductor of electricity. Malleable(can be beaten into thin sheets on hammering) Good conductor of heat Light and strong

COPPER

USE In electrical cables

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PROPERTY Good conductor Ductile (can be drawn into thin wires.)

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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. SEE TABLE 3 FROM PAGE NO 40 Uses of Non Metals Nitrogen

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For making fertilizers Help in making proteins.

Phosphorous

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In match industry As fertilizers

Iodine Sulphur

• • • •

As antiseptic In fire crackers In making gun powder 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) Copper b) 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.