Group 1 - Alkali metals

• As you go down Group 1:

  • Reactivity increases
  • Melting and boiling points decrease
  • Relative atomic mass increases
• Group 1 elements react with a range of substances to make ionic compounds, such as:

  • Metal + Water → Metal hydroxide + Hydrogen
  • Metal + Chlorine → Metal chloride
  • Metal + Oxygen → Metal oxide
• Group 1 properties:

  • Soft
  • Low density
  • Low melting point
• Ionic compounds made by Group 1 metals:

  • Usually form white solids
  • Can dissolve in water to form colourless solutions
• Alkali metals recating with water observations:

  1. Lithium ~ slow reaction, fizzes steadily, gradually disappears
  2. Sodium ~ heat released causing hydrogen to catch fire, sodium piece moves around, piece melts and disappears quickly
  3. Potassium ~ enough heat released for hydrogen to burn with a lilac flame, moves around a lot, disappears very quickly
• Colours of flames when group 1 burns in oxygen;

  • Li - Red
  • Na - Yellow/orange
  • K - Lilac