Reactivity Series
The reactivity series tells us how well a metal reacts and therefore how easy to extract the metal from their ores:
Very reactive: Potassium (K), Sodium (Na), Calcium (ca)
Fairly reactive: Magnesium (Mg), Aluminium (Al), [Carbon (C)], Zinc (Zn)
Not very reactive: Iron (Fe), Lead (Pb), [Hydrogen (H)], Copper (Cu)
Not at all reactive: Silver (Ag), Gold (Au)
The five metals above carbon need electrolysis (use of electrical energy) to split up the ore into its elements. The next three elements can be extracted by reaction with coke (carbon) because they are less reactive than carbon and will be 'displaced' by carbon. The last three metals are unreactive and can be found on their own in the ground and in rivers.
Reactions of Metals
Reaction of metals with oxygen makes an oxide: Metal + Oxygen --> Metal Oxide. The metal oxide formed is called a base.
Potassium and sodium react without heating. Other metals such as magnesium and zinc react on heating. Copper forms only a black surface coating of copper oxide when heated in oxygen or air.
Potassium, sodium, calcium and magnesium burn very easily with a bright flame. Aluminium reacts with oxygen and makes a thick layer of oxide that stop the reaction. Zinc, iron, lead and copper react slowly with air when heated. Silver and gold do not react with oxygen.
Metals above hydrogen will always react with water to produce hydrogen.
Reaction of very reactive metals with water makes hydroxides: Reactive Metal + Water --> Metal Hydroxide + Hydrogen.
Less reactive metals react with steam to make metal oxides: Less Reactive Metal + Steam --> Metal Oxide + Hydrogen.
Potassium and sodium react vigorously with cold water and produce hydrogen and an alkali in the water (KHO/NaHO). With potassium, the hydrogen gas catches light. Calcium reacts slowly with cold water --> Ca(HO)2 + H2 and the calicum sinks in the water.
Magnesium, aluminium and zinc do not react with cold water but do react with steam. Iron only reacts partially with steam.
Lead, copper, silver and gold do not react with water or steam.
Displacement Reactions
Displacement means 'taking the place of'. The rule of displacement reaction is that 'A more reactive metal will replace a less reactive metal from its compound'.
If a more reactive metal is put into a solution of a less reactive metal compound, the less reactive metal of the compound will be displaced. When a msgnesium strip is put into a copper sulphate solution, the copper sulphate goes colourless and the copper coats the magnesium strip:
Magnesium (Mg) + Copper Sulphate (CuSO4) (aq) → Magnesium Sulphate (MgSO4) (aq) + Copper (Cu)
When a copper strip is put into a zinc sulphate solution, there is no reaction because zinc is more reactive than copper (it is above copper in the reactivity series).
Reactions of Metals with Acids
Metals above hydrogen in the reactivity series will react with acids and the general reaction is:
Metal + Acid --> Salt + Hydrogen
Potassium, sodium and calcium react violently with dilute acids. Magnesium, aluminium, zinc and iron react fairly well with dilute acids. Lead, copper, silver and gold do not react with dilute acids. Examples of reactions:
magnesium (Mg) + hydrochloric acid (2HCl) --> magnesium chloride (MgCl2) + hydrogen (H2)
zinc (Zn) + sulphuric acid (H2SO4) --> zinc sulphate (ZnSO4) + hydrogen (H2)
magnesium (Mg) + nitric acid (2HNO3) --> magnesium nitrate (Mg(NO3)2) + hydrogen (H2)
Actually hydrogen is rarely produced with nitric acid due to complicated further reactions.
The test for hydrogen gas is the 'squeaky pop' when a lighted splint is put near the gas.