Physical Properties of Metals

1
Physical Properties of Metals
Property Statement Application
melting point Solid at room temperature (except Hg) Hg used in thermometers
density Vary from less than water (sodium) to very dense (lead) Al used in aircraft because of low density
thermal conductivity All metals conduct heat well Al and stainless steel used in cooking pans
malleability Metals ca be bent into different shapes Car bodies made of flat steel sheets
strength Some metals are strong Iron used to make girders and reinforce concrete
electrical conductivity All good conductors as solid or liquid Cu and Al used to make electrical wires
2
Alloys

• The properties of metals can be improved by
  making them into metals. For example, aluminium
  is very lightweight and so would be ideal for
  making aeroplanes. However, it isnt strong
  enough to hold passengers and their luggage.
• An alloy is formed when two or more metals or
  metals with non-metals are mixed together.
• Alloys are usually made by melting the mixture
  and then allowing it to cool until it has
  solidified.
• An alloy enhances the properties of a metal to
  make it more useful. Alnico (alloy made of
  aluminium, nickel and cobalt) keeps the
  lightweight property but adding the other metals
  makes it much stronger.

3
Examples of Alloys
Name of Alloy Metals present Uses
brass copper and zinc Door handles and fittings
bronze copper and tin statues
solder tin and lead Soldering metals together
stainless steel Iron, chromium and nickel Cutlery, kitchen sinks
4
Reactivity of Metals

• A list that places metals in order of their
  readiness to take part in chemical reactions
• Reactive metals are at the top and unreactive
  metals are at the bottom
• Reactions with oxygen, water and dilute acid can
  be used to put metals in order
• The speed of a reaction can determine reactivity

5
How do I remember the Reactivity Series

• Use your data booklet same as the
  Electrochemical Series except for the first 4.
  Remember the first 4 by using
• Pupils So Love Chemistry
• potassium sodium lithium calcium
• or

6

• Remember the following mnemonic
• Please Send Lazy Charlie
• potassium sodium lithium calcium
• McLean A Zebra If The
• magnesium aluminium zinc
  iron tin
• Lean Horse Cant Munch
• lead hydrogen copper mercury
• Sweet Green Plants
• silver gold platinum
• Hydrogen is a non metal but you will see why
  it is included in Unit 4B

7
Metals as Resources

• We obtain metals from rocks in the Earth known as
  metal ores.
• An ore is a naturally occurring compound of a
  metal e.g iron ore contains iron oxide
• Extraction involves obtaining a metal from its
  ore
• Metals are often recycled as we have a finite
  (limited) supply
• Unreactive metals can be found on Earth as the
  metals themselves. They are uncombined i.e have
  not formed compounds e.g gold and silver

8
The date of discovery of a metal
The cost of a metal
The value of recycling a metal
Can be related to two factors
Whether it occurs naturally as an element or how
easily it is extracted from its ores i.e how
reactive it is
How abundant (how plentiful) it is
9

• Silver and gold have been known since earliest
  civilisation because they are unreactive and so
  were found uncombined
• Aluminium and magnesium were not discovered until
  the nineteenth century since they are quite
  reactive and very difficult to extract from their
  ores
• The cost of recycling aluminium is less than the
  cost of extracting aluminium from its ore

10
Production of Iron from its Iron Ore

• In industry, this is carried out in a blast
  furnace

CO removes oxygen from iron ore Fe2O3 3CO
2Fe 3CO2 CO2 reacts with carbon to
form CO CO2 C 2CO Coke
burns in the blasts of hot air to form CO2 C
O2 CO2