Group 1 (Alkali Metals)

• How many electrons do Alkali Metals have on their outer shell?

  1
• Describe the observations and products of reacting Lithium with water.

  • Lithium floats
  • fizzes steadily
  • becomes smaller until it eventually disappears
  • ithium + water → lithium hydroxide + hydrogen
• Describe the observations and products of reacting Sodium with water.

  • melts to form a ball that moves around on the surface of the water
  • fizzes rapidly before it disappears
  • sodium + water → sodium hydroxide + hydrogen
• Describe the observations and products of reacting Potassium with water.

  • melts and floats
  • moves around very quickly on the surface of the water
  • self-ignites, which also ignites the hydrogen gas
  • resulting in sparks and a lilac flame
  • sometimes a small explosion at the end of the reaction
  • potassium + water → potassium hydroxide + hydrogen
• Describe the observations and products of reacting Lithium with oxygen.

  •  tarnishes slowly due to its relatively slow reaction with oxygen
  • lithium + oxygen → lithium oxide
• Describe the observations and products of reacting Sodium with Oxygen.

  • tarnishes more quickly than lithium
  • sodium + oxygen → sodium oxide
• Describe the observations and products of reacting Potassium with Oxygen.

  • tarnishes so quickly that it is difficult to see that potassium is actually a shiny metal
  • potassium + oxygen → potassium oxide
• Describe the observations and products of reacting Lithium with a halogen.

  • all the reactions of lithium with halogens produce a crimson flame
  • lithium+[halogen]→lithium[halide]
  • lithium+[chlorine]→lithium[chloride]
• Describe the observations and products of reacting Sodium with a halogen.


  • all the reactions of sodium with halogens produce a yellow flame
  • sodium+[halogen]→sodium[halide]
  • sodium+[chlorine]→sodium[chloride]
• Describe the observations and products of reacting Potassium with a halogen.


  • all the reactions of potassium with halogens produce a lilac flame
  • potassium+[halogen]→potassium[halide]
  • potassium+[chlorine]→potassium[chloride]
• Explain why the reactivity of Group 1 increases as you go down the group.

  As you go down the group, the number of shells increases, this means that there is a greater atomic radius as you go down the group.

  Therefore, there is less of an attraction between the outermost shell and the nucleus as you go down the group, thus, it is easier to lose an electron as you go down the group and the reactivity of the element increases.