1. 10.5.1 Patterns of Reactivity
IGCSE Chemistry
Patterns of Reactivity

2. Comparing orders of reactivity
When the orders of reactivity of metals with water, oxygen and air are compared, there is a pattern of results.
with water
potassium
sodium
lithium
magnesium
copper
silver
gold
with oxygen
magnesium
iron
copper
with acid
calcium
magnesium
aluminium
zinc
iron
lead
copper
Combining the information from all the reactions of metals with water, oxygen and air gives an overall order of reactivity
called the reactivity series.

3. increasing reactivity
The reactivity series
The reactivity series is the list of metals placed in order of their reactivity.
One way to remember this order is to learn this silly sentence:
potassium
sodium
calcium
magnesium
aluminium
zinc
iron
lead
copper
silver
gold
Please
send
Charlie’s
monkeys
and
zebras in
lead
cages
securely
guarded!
increasing reactivity

4. What is the order of metals?

5. Using the reactivity series
The reactivity series can be used to make predictions about the reactions of metals.
Predictions can be made about simple reactions of metals with oxygen, water and acids.
Predictions can also be made about more complex reactions where one metal is competing with another.
potassium
sodium
calcium
magnesium
aluminium
zinc
iron
lead
copper
silver
gold
increasing reactivity

6. Simple reactions – predictions
Use the reactivity series to predict if a reaction will take place and how intense the reaction will be.
Metal
React with
Prediction
gold
acid
calcium
water
sodium
oxygen
silver
zinc
potassium
sodium
calcium
magnesium
aluminium
zinc
iron
lead
copper
silver
gold
no reaction
fizzing
burns vigorously
very slow reaction
burns moderately

7. When does displacement happen?
The reactivity series can be used to predict if a metal will react with a metal compound (e.g. chloride, nitrate or sulfate).
If the metal is more reactive than the metal in the compound,
it competes with the less reactive metal.  +
less reactive metal compound
more reactive metal +
less reactive metal
more reactive metal compound
The more reactive metal pushes out, or displaces, the less reactive metal from its compound.
If the metal is less reactive than the metal in the compound,
it will not compete and so there is no reaction. +
no reaction 
more reactive metal compound
less reactive metal

8. Displacement reactions – examples
The reactivity series can be used to predict if a metal will react with a metal compound.
Will magnesium react with copper chloride? 
copper chloride +
magnesium
copper +
magnesium chloride
Magnesium is a more reactive metal than copper, so magnesium displaces the copper from its compound.
Will silver react with magnesium chloride? 
magnesium chloride +
silver
no reaction
Silver is a less reactive metal than magnesium, so silver does not displace the magnesium from its compound.

9. Displacement reactions – observation
This photograph shows what happens when magnesium reacts with copper sulfate.
Why does the blue colour of the coppers sulfate solution gradually disappear during this reaction?
before
after
copper +
magnesium sulfate 
copper sulfate
magnesium
Magnesium is a more reactive metal than copper and so the magnesium displaces the copper from the copper sulfate solution. This is why the blue colour disappears.

10. Displacement of sulfates – predictions
Use the reactivity series to predict if there is a reaction when these metals are added to different metal sulfate solutions.
magnesium sulfate
zinc
sulfate
iron
copper sulfate
magnesium
copper
metal sulfate
solution
metal             
= displacement reaction
= no reaction 

11. Displacement of sulfates – magnesium
Does magnesium react with and displace these metal sulfates and if so what products are formed? 
copper sulfate +
magnesium
magnesium sulfate +
copper  Mg +
CuSO4 
MgSO4 Cu 
zinc
sulfate +
magnesium
magnesium sulfate +
zinc  Mg +
ZnSO4 
MgSO4 Zn 
iron
sulfate +
magnesium
magnesium sulfate +
iron  Mg +
FeSO4 
MgSO4 Fe

12. Displacement of sulfates – zinc
Does zinc react with and displace these metal sulfates and if so what products are formed?  
magnesium sulfate +
zinc
no reaction 
iron
sulfate +
zinc
zinc
sulfate +
iron  Zn +
FeSO4 
ZnSO4 Fe 
copper sulfate +
zinc
zinc
sulfate +
copper  Zn +
CuSO4 
ZnSO4 Cu

13. Displacement of sulfates – iron
Does iron react with and displace these metal sulfates and if so what products are formed?  
magnesium sulfate +
iron
no reaction  
zinc
sulfate +
iron
no reaction 
copper sulfate +
iron
iron
sulfate +
copper  Fe +
CuSO4 
FeSO4 Cu

14. Displacement of sulfates – copper
Does copper react with and displace these metal sulfates and if so what products are formed?  
magnesium sulfate +
copper
no reaction  
zinc
sulfate +
copper
no reaction  
copper sulfate +
copper
no reaction

15. Displacement of oxides
Displacement reactions can also occur between a metal and a metal compound that is a solid. 
iron
oxide +
aluminium
iron +
aluminium oxide
The more reactive aluminium wins the oxygen from the less reactive iron. The reaction gets so hot that the iron melts!
This is the Thermit reaction and is used to weld railway lines.

16. Displacement of oxides – predictions
Use the reactivity series to predict if there is a reaction when each mixture of a metal and a metal oxide is heated.
zinc
oxide
iron
copper oxide
copper
metal
oxide
metal       
= displacement reaction
= no reaction 

17. Displacement of oxides – zinc
Does zinc react with and displace these metal oxides and if so what products are formed? 
copper oxide +
zinc
zinc oxide +
copper  Zn +
CuO 
ZnO Cu 
iron oxide +
zinc
zinc oxide +
iron 
3Zn +
2Fe2O3 
3ZnO
2Fe
Zinc is the more reactive than copper and iron.

18. Displacement of oxides – iron
Does iron react with and displace these metal oxides and if so what products are formed?  
zinc oxide +
iron
no reaction 
copper oxide +
iron
iron oxide +
copper 
2Fe +
3CuO 
Fe2O3
3Cu
Iron is less reactive than zinc but more reactive than copper.

19. Displacement of oxides – copper
Does copper react with and displace these metal oxides and if so what products are formed?  
zinc oxide +
copper
no reaction  
iron oxide +
copper
no reaction
Copper is less reactive than zinc and iron and will not displace either of these metals.

20. Displacement reactions – activity
Use the reactivity series to predict if each mixture will react.
Reactants
Reaction?
iron oxide
magnesium
potassium
sodium
calcium
magnesium
aluminium
zinc
iron
lead
copper
silver
gold 
copper sulfate
zinc 
potassium
hydrochloric acid  
gold
iron chloride 
calcium
sodium chloride
calcium
oxygen 

21. Displacement reactions – activity
Use the reactivity series to predict if each mixture will react and complete the word equation. 
aluminium oxide +
magnesium
magnesium oxide +
aluminium 
iron chloride +
magnesium
magnesium chloride +
iron 
zinc oxide +
silver
no reaction 
gold nitrate +
copper
copper nitrate +
gold

22. reactive – A substance that reacts quickly or easily.
Glossary
displaced metal – The metal that is pushed out of a compound by a more reactive metal.
displacement – A reaction in which a more reactive metal replaces a less reactive metal in a compound.
reactive – A substance that reacts quickly or easily.
reactivity – How quickly or easily a substance will react.
reactivity series – The list of metals placed in order of their reactivity starting with the most reactive.
tarnished – A metal that has become dull after reacting with water and oxygen in the air.
Thermite reaction – The displacement reaction between aluminium and iron oxide that is used to weld railway lines.
unreactive – A substance that reacts very slowly or
does not react at all.