Chemistry Unit 1

Group 1- The Alkali Metals

• Silvery solids
• Their hydroxides dissolve in water to give an alkaline solution.

 As you go down the group the metals become:

1) Bigger- there is one extra full shell of electrons for each row you go down.

2) More reactive- the outer electron is further away from the nucleus so is more easily lost.

3) Higher density- the atoms have more mass, the three at the top (lithium, sodium and potassium) are less dense then water.

4) Lower melting and boiling point.

• The metals are very reactive, have to be stored in oil and handled with forceps
• They have 1 outer shell electron which makes them very reactive, and gives them all the similar properties.
• They are keen to lose that one outer shell electron and form a 1+ ion.
• Always form ionic compounds.

Reaction with Water

• When lithium, sodium and potassium are put in water they react very vigourously.
• Move around the surface, fizzing.
• Produce hydrogen, potassium…