1. Groups of elements
Chapter 34

2. Alkali Metals?(Li, Na K)
The Alkali metals are the elements of group 1 of the periodic table.
Each element has one electron in its outer shell.
Because of this, the elements have similar chemical properties.

3. Physical properties The Alkali metals are soft and easy to cut.
They have a shiny appearance when cut.
They are less dense than water and float on water.
They conduct electricity.

4. Chemical properties.
They react with Oxygen to form oxides and burn rapidly with a coloured flame.
4Li + O2 --> 2Li2O
4Na + O2 --> 2Na2O
4K + O2 --> 2K2O

5. Reaction with Water
The alkali metals react vigorously with water. Hydrogen gas is given off and a hydroxide compound is formed.
Sodium Water > Sodium Hydroxide Hydrogen
Potassium + Water > Potassium Hydroxide Hydrogen
Lithium Water > Lithium Hydroxide Hydrogen

6. Reactivity of the alkali metals
Reactivity increases as you go down the group
Of the alkali metals that we study, Potassium is the most reactive and Lithium is the least reactive.
The reason for this is that the outer electron in potassium is further away from the nucleus of the atom than the outer electron of lithium is from its nucleus.

7. Uses of the alkali metals
Lithium is used in the manufacture of batteries for watches and cameras.
Sodium is used for street lights.
Potassium compounds are used as fertilisers.