1. 9F Patterns of reactivity
Metals and the air
The reactivity series
Metal extraction

2. 9F Patterns of reactivity
Metals and the air

3. is that most cars are made of steel, which is mainly iron.
9F The trouble with cars...
The trouble with cars...
is that most cars are made of steel, which is mainly iron.
Do you think these materials would last longer than iron?
zinc
aluminium
gold
plastic
wood
glass
Why do we make cars out of steel?

4. But a gold bridge would be very expensive!
9F Corrosion
Many metals react with oxygen in the air. Over time, a thin layer of metal oxide covers the surface of the metal. We call this tarnishing.
Some metals carry on reacting below the surface and their structure is destroyed. This corrosion wears away the metal.
You can prevent this by painting the metal. How does the paint stop the metal tarnishing?
Or you can choose a metal that does not react with the air – like gold.
But a gold bridge would be very expensive!

5. Meet the starters in the metal-corrosion Gold Cup!
9F The metal-corrosion Gold Cup
Meet the starters in the metal-corrosion Gold Cup!
The hot favourite is potassium. Gold has poor prospects – people say it won’t run well.
Who’s your money on?
They’re under starters orders...

6. Which metal corroded fastest? Which didn’t corrode at all?
9F The metal-corrosion Gold Cup
Which metal corroded fastest?
Which didn’t corrode at all?
Were your predictions correct?

7. Match each word or phrase with its correct meaning.
9F Keywords
rusting corrosion unreactive metal oxide tarnishing patina
Match each word or phrase with its correct meaning.
a compound containing only a metal and oxygen
a metal breaking down by reacting with oxygen (and sometimes moisture)
to gather a thin layer of discoloration by reacting with the air
describes a material that does not react
a thin layer of green on the surface of copper
the corrosion of iron, which reacts with oxygen and water to form flaky iron oxide
corrosion
metal oxide
tarnishing
unreactive
patina
rusting

8. 9F What can you trust about rust?
True or False?
4. All metals corrode at the same rate at the same temperature.
5. Aluminium is special because of its oxide layer.
3. Metals will not corrode if air and water cannot get to them.
2. Nitrogen from the air is the gas that iron reacts with when it starts to corrode.
1. Rusting is a type of corrosion reaction.
Aluminium doesn’t corrode because its oxide layer protects it.
TRUE!
Metals corrode at different rates: the more reactive a metal is, the more quickly it will corrode.
FALSE!
Corrosion needs oxygen from the air, and sometimes water takes part in the reaction too.
TRUE!
It’s oxygen!
FALSE!
We use the word ‘rusting’ for the corrosion of iron, since the flaky red iron oxide that forms is called rust.
TRUE!

9. 9F Patterns of reactivity
The reactivity series

10. Anyone like to explain what reactivity means?
9F He’s just so reactive!
Anyone like to explain what reactivity means?
Which is the more reactive atom?

11. What does reactivity mean?
9F Reactivity in chemistry
What does reactivity mean?
Elements that are reactive readily take part in reactions with other chemicals.
But an element might react very quickly with one chemical and hardly at all with another. So is it reactive or not?
To compare the reactivity of different elements, we might see how easily they react with oxygen.
Some metals corrode in minutes out on the bench.
Others take longer to corrode, unless you heat them.

12. We can list metals in order of how quickly they react with oxygen.
9F The Gold Cup again?
We can list metals in order of how quickly they react with oxygen.
speed of reaction with oxygen
least reactive
most reactive
This ranking of metals according to reactivity is called the reactivity series.

13. What if we react different metals with acid?
9F Reaction of metals with acid
What if we react different metals with acid?
iron – the metal reacts slowly, producing a few bubbles
copper – no bubbles, no reaction with acid
lead – the metal reacts very slowly, producing very few bubbles
magnesium – the metal reacts quickly with the acid, producing lots of bubbles
sodium – the metal bursts into flames, a very strong reaction

14. reactivity series with
9F What about water?
We can also rank metals by their reaction with water.
Compare with the reactivity series for oxygen and acid.
reactivity series with
oxygen
acid
water
potassium
sodium magnesium zinc iron lead copper gold
potassium sodium magnesium zinc iron lead copper gold
The reactivity series is very useful. How can we learn it?

15. metal symbol useful mnemonic?
9F Remembering the series
metal
symbol
useful mnemonic?
potassium sodium magnesium aluminium zinc iron lead hydrogen copper gold
K Na Mg Al Zn Fe Pb H Cu Au
Kangaroos Naturally Muck About in Zoos For Purple Hippos Chasing Aardvarks
Come on, you can think of a better mnemonic!

16. Put each metal in the correct box in the reactivity series.
9F Test your reactivity
Put each metal in the correct box in the reactivity series.
sodium
aluminium
lead
hydrogen
copper
gold
potassium
magnesium
magnesium zinc
iron potassium
zinc
iron

17. The reactivity series allows you to make predictions.
9F Using the series
The reactivity series allows you to make predictions.
Choose from the box below. What will happen when you mix...
...a metal
…and an acid?
potassium
hydrochloric acid
magnesium
iron
copper
gold
very violent reaction
fast reaction
gas bubbles form slowly
nothing happens
nothing happens
nothing happens gas bubbles form slowly
fast reaction nothing happens
very violent reaction

18. Magnesium is more reactive than copper.
9F Feeling a bit displaced?
A displacement reaction happens when one metal replaces another one in a compound.
Magnesium is more reactive than copper.
Magnesium displaces copper from copper sulphate solution.
What evidence can you see that a reaction has happened?
Complete the word equation.
magnesium + copper sulphate magnesium sulphate + ?

19. A more reactive metal displaces a less reactive one.
9F Predicting displacement reactions
A more reactive metal displaces a less reactive one.
True or false?
potassium most reactive
sodium
magnesium
zinc
iron
lead
copper
gold least reactive
Iron displaces gold but cannot displace magnesium.
Zinc displaces magnesium from magnesium nitrate solution.
Copper displaces sodium compounds from solution.
Magnesium displaces copper from copper sulphate, and the blue colour disappears.
False!
True!
False!
True!

20. Write a word equation for this reaction.
9F A model for displacement reactions
This model will help explain displacement reactions.
Think of reactivity as aggression!
Write a word equation for this reaction.

21. 9F Patterns of reactivity
Metal extraction

22. All the metals we use are found in the Earth.
9F Finding metals
All the metals we use are found in the Earth.
To extract the metal, we first dig up the ore.
Then we carry out chemical reactions to get the pure metal out of its compound.
The cost of a metal depends on:
how hard it is to find and dig up the ore
how reactive the metal is.
Why is the reactivity so important?

23. Write a word equation for copper oxide reacting with carbon.
9F The easy ones are at the bottom
Gold and silver are simple to extract. You might find lumps lying around in river beds (if you’re lucky!). You just pick them up.
potassium sodium magnesium aluminium (carbon) zinc iron lead copper silver gold
You can also find copper metal in some rocks. Sometimes you find copper oxide in ore, but it’s easy to extract.
Carbon is cheap and plentiful (as coal). If you heat copper oxide with carbon, the carbon takes the oxygen to make carbon dioxide and leaves copper metal. What sort of reaction is this?
Write a word equation for copper oxide reacting with carbon.

24. Zinc needs a higher temperature than lead. Why?
9F Getting tougher
Zinc, iron and lead are found in the Earth as compounds, in ores. Like copper, they can be extracted by heating with carbon.
potassium sodium magnesium aluminium (carbon) zinc iron lead copper silver gold
The carbon takes the oxygen from the metal to make carbon dioxide. It often needs a very high temperature: about 700°C for iron.
Zinc needs a higher temperature than lead. Why?
Write a word equation to show the displacement reaction when lead oxide reacts with carbon.

25. 9F The downright awkward are at the top
Potassium, sodium, magnesium and aluminium are very difficult to extract. They are very reactive. They hold on tightly to the other elements in their compounds.
potassium sodium magnesium aluminium (carbon) zinc iron lead copper silver gold
Carbon cannot displace these elements no matter how hard you heat it. Why not?
We use electrolysis to extract these metals from their ores. An electric current passes through the molten mineral. This breaks it down so we get out the pure metal. The process is very expensive.

26. 9F Extract the truth!
True or False?
3. Gold occurs in a mineral that is difficult to break down. That is why gold is so expensive.
4. A metal that corrodes quickly will be easy to extract from its ore.
2. More reactive metals are more difficult to extract from their minerals than less reactive metals.
1. Iron is easier to extract from its ore than sodium.
If a metal corrodes easily it means it is very reactive. So it will be difficult to extract.
FALSE!
Gold often exists as the pure metal and needs no extraction. It’s expensive because it is rare.
FALSE!
Think about the ‘reactivity dog’. The scarier the dog (the more reactive the metal), the more difficult it is to remove the bone (the other elements).
TRUE!
Iron is less reactive. It just needs heating with carbon. Sodium needs electrolysis.
TRUE!