2. Before metals
• Pre 9000 BCE - Stone Age
• Malachite (a green copper ore) and Hematite (a red
iron ore) ground to powder and used for art work
• Coloured ores used as jewellery
• All tools made from stone and wood
3. Discovery of metals
• Earliest known metals
were “native”metals
• Found as nuggets
• Copper, silver, gold
4.
5. Ores
• Compared to pure
metals, ores were
just rocks
• No ‘metallic
splendour’
6. Native Metals vs Ores
Native metal Ore
Lustre (Shiny) Some are glittery
Malleable (can be hammered
into sheets) Shatter when hit by a
Ductile (can be drawn into hammer
wires)
Conduct electricity and heat Don’t conduct electricity and
heat
Insoluble Insoluble
Don’t burn Don’t burn
7. Native metals could
•
be....
Converted to a state similar to ores by heating with
sulphur
• Earliest forms of ores (metal sulphides)
• Formed naturally by heat and sulphur from
volcanic activity
• This can also be done by heating in air (oxygen)
• This form of ore (metal oxides) developed
naturally after plant life formed on Earth.
9. Major Discovery!
• Ores can be converted to metal by heating with
charcoal
• Discovered by accident?
• Copper bearing rocks around a camp fire
• Inefficient method but...
•
10. Copper Smelting
• Development of a simple clay kiln plus use of
bellows - much more efficient due to increased
temperature
12. Progress
• Without the discovery of the smelting process...
• No extraction of other “non-native” metals such
as tin or iron
• No Bronze or Iron Ages (and no further progress!)
14. Alloys
• A mixture of metals
• Have different properties to the metals that make
them up
• Bronze - a mixture of copper and tin
• Brass - a mixture of copper and zinc
15. Reactivity series
A list showing metals in order of their reactivity
(from most to least)
• Magnesium Going from bottom to top, the
metals:
• Aluminium
• increase in reactivity;
• Zinc • lose electrons more readily to
form positive ions;
• Iron • corrode or tarnish more
readily;
• Lead
• require more energy (and
• Copper different methods) to be
separated from their ores
Note: This list is a partial list
16. Metal Reactivity Extraction
Potassium K
Sodium Na
Lithium Li React with water
Strontium Sr Electrolysis
Calcium Ca
Magnesium Mg
Aluminium Al
Zinc Zn
Chromium Cr
Iron Fe
React with acids
Cadmium Cd
Smelting with coke
Cobalt Co
Nickel Ni
Tin Sn
Lead Pb
Copper Cu
Silver Ag
Heat or physical
Mercury Hg Highly unreactive
extraction
Gold Au
Platinum Pt
18. Transition Metals
•Cobalt - Pink •Note all bunched together in
terms of weight
•Manganese - Orange
•All the coloured salts are
multi-valency
•Copper/Nickel - Blue or
Greenish Blue
•Valency = the number of
bonds an atom will form with
•Iron - pale Green or Red
another element
•Titanium/Zinc- White
•Vanadium - Yellow
•Chromium - Yellow/Red
