Group 1 (Oxford AQA IGCSE Chemistry): Revision Note

Properties & Reactions of the Alkali Metals

• The Group 1 metals are located in the first column of the Periodic Table

  • They are known as the alkali metals

• The Group 1 metals are:

  • Lithium

  • Sodium

  • Potassium

  • Rubidium

  • Caesium

  • Francium

Group 1 of the Periodic Table

• Are low density metals

  • The first three elements in the group are less dense than water

• React with non-metals to form ionic compounds

  • E.g. sodium chloride is a white solid formed by the reaction between sodium and chlorine

    $\mathrm{sodium}+\mathrm{chlorine}\to \mathrm{sodium}\mathrm{chloride}$

  • The metal ion will have a charge of +1

  • The ionic compound formed is a white solid that dissolves in water to form a colourless solution

• React with water to produce a metal hydroxide and hydrogen gas

  • E.g. sodium reacts with water to form sodium hydroxide and hydrogen gas

    $\mathrm{sodium}+\mathrm{water}\to \mathrm{sodium}\mathrm{hydroxide}+\hspace{0.17em}\mathrm{hydrogen}$

The reaction between sodium and water

• The hydroxide dissolves in water to form alkaline solutions - hence the name 'alkali metals'

• If universal indicator is added to the solution it will turn purple/blue

Trends in Group 1

• The reactivity of the Group 1 metals increases as you go down the group

• When a Group 1 element reacts, its atoms only need to lose the 1 electron in the outer shell

  • When this happens,+1 ions are formed

• Reactivity increases going down Group 1 because:

  • The number of shells increases

  • This means that the outermost electron gets further away from the nucleus

  • There are weaker forces of attraction between the outermost negative electron and the positive nucleus

  • Less energy is required to overcome the force of attraction

  • This means the outer electron is lost more easily

The electronic configurations of Group 1 elements