group 1 elements

• Group 1 metals

  • Very reactive with water, oxygen, chlorine
  • Only has one electron on outer shell forming 1+ ion
• Reactivity of group 1 metals

  • Increases down the group as the negative outer electron is further away from the nucleus so its more easily lost due to attraction being weaker
  • Increases down the group due to more shielding
• Boiling point of group 1 metals

  • Decreases down the group
• When group 1 reacts with water

  Forms a metal hydroxide + hydrogen gas
• Reactions of group 1 metals with water


  • Lithium floats, fizzes steadily and becomes smaller until it disappears
  • Sodium melts to form a ball that moves around on the surface, fizzes rapidly before disappearing
  • Potassium melts and floats, moves around quickly on the surface, self-ignites which also ignites the hydrogen gas, results in sparks and a lilac flame, sometimes a small explosion
• When group 1 reacts with oxygen


  Forms a metal oxide
• Reactions of group 1 metals with oxygen

  • Tarnishes away slowly
  • Combustion can take place where the metals burn, potassium is most vigorous
• When group 1 reacts with a halogen


  Forms a white solid
• Flame colours of group 1 metals

  • Lithium = crimson flame
  • Sodium = yellow flame
  • Potassium = lilac flame
• Hydrogen squeeky pop test for group 1 metals with water

  1. Burning splint held at open end of test tube

  2. Squeaky pop heard
• Burning splint


  Identifies hydrogen
• Squeaky pop


  • Indicates presence of hydrogen
  • Hydrogen burns rapidly and reacts with oxygen in air, producing characteristic squeaky pop