1. Write word equations for the reactions between the following metals and water: a. Lithium b. Potassium
2. Write word equations for the reactions between the same metals and oxygen. 3. Explain why group 1 of the periodic table are known as the alkali metals.
The table below summarises the properties and uses of the alkali metals and alkaline earth metals.
Alkali metals (group 1 metals)
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Have low meting points
Dull quickly in air but are shiny when freshly cut (they are soft metals stored in oil)
Are more reactive as you go down the group
Lithium is used in batteries. Sodium is used in street lamps and potassium is used in making fertilisers
Corrosion of Metals
Corrosion is the gradual reaction of metals with water and oxygen in their environment.
A metal oxide is formed when a metal reacts with water and oxygen.
A metal oxide you will be familiar with is iron oxide (rust). Iron oxide forms on the surface of iron but it is soft and flakes off allowing the iron underneath to corrode further.
Oxygen and water are both needed for the corrosion of iron to take place. If one factor is missing, the iron will not rust.
The green colour of copper roofs is due to corrosion.
Alkaline earth metals (group 2 metals)
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Have higher melting points than the alkali metals
Get more reactive as you go down the group
Magnesium is used in fireworks as it burns brightly, and calcium in our diet makes teeth and bones stronger
