Metal ores and mining

• Ores are naturally occurring rocks found in the Earth’s crust.

• They contain metal/metal compounds in sufficient amounts to make it worthwhile extracting them

• Ores are mined and maybe concentrated before the metal is extracted and purified

potassiumsodiumcalcium

magnesiumaluminium

zinciron

copper

goldincre

asin

g r

eacti

vit

yMetals above carbon in the reactivity series must be extracted using electrolysis. Electrolysis can also be used to purify copper.Metals less reactive than carbon can be extracted from their ores by reduction using carbon, coke or charcoal.Platinum, gold, silver and copper can occur native

and do not need to be extracted.

lead

silver

The reactivity of a metal determines how it is extracted.

(carbon)

(hydrogen)

platinum

Reducing iron oxide

• Metals that are less reactive than carbon can be extracted from their oxides by reduction with carbon• The metal is reduced because it loses oxygen

• For example, iron oxide is reduced in the blast furnace to make iron

Electrolysis

• Metals that are more reactive than carbon, such as aluminium, are extracted by electrolysis of molten compounds.

• The use of large amounts of energy in electrolysis makes these metals expensive

• Copper can be purified by electrolysis. • The supply of copper-rich ores is limited and so copper can also be

obtained from solutions of copper salts by electrolysis or by displacement using scrap iron

Recycling metals

• We should recycle metals because extracting them uses limited resources and is expensive in terms of energy and effects on the environment

Ac Rf Db Sg Bh Hs Mt Ds Rg

La Hf Ta W Re Os Ir Pt Au Hg

Y Zr Nb Mo Tc Ru Rh Pd Ag Cd

Sc Ti V Cr Mn Fe Co Ni Cu Zn

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group 2 group 3

Here, the word

‘transition’ is used to mean ‘in-between’.

The elements in the central block of the periodic table are known as transition

metals(between group 2 and group 3)

Properties of Transition metals

Like other metals • They are good conductors of heat and electricity• They can be bent or hammered into shape• They are useful as structural materials and for making things that must allow heat or

electricity to pass through them easily

Metals and their usesTransition

metalsUses Properties

IronAlloyed with carbon to

make steel

Brittle by itself, low carbon steel easily shaped, high carbon steel are harder, stainless steel resistant to corrosion

CopperUsed for electrical wires

and plumbing

Good conductor of electricity and heat, can be bent but is hard enough to make

pipes

PlatinumReduces pollution from car exhausts, jewellery

Very low reactivity. Hard to extract from its ore as it can’t be reduced, which

makes it expensive.

TitaniumUsed to make artificial

hip jointsLow density, resistant to corrosion.

NickelIs a catalyst in

margarine productionSpeeds up the reaction but does not take

part in it.

Another important

metalUses Properties

AluminiumTransport, construction,

packaging

Low density, resistant to corrosion. Hard to extract from its ore as it can’t be reduced, which makes it expensive.

- Most metals in everyday use are alloys as pure copper, gold and aluminium are too soft for most uses

- They are mixed with other similar metals to make them harder

Impure iron

• Iron from the blast furnace contains about 96% iron. • The impurities make it brittle and so it has limited

uses

Alloys can be designed to have properties for specific uses

• Steels are alloys of iron and carbon. Some steels contain other metals.

• Low carbon steels are easily shaped, high carbon steels are hard and stainless steels are resistant to corrosion

Low carbon steelHigh carbon steel

Stainless steel

Some steels contain other metals.