2a - group 1 (alkali metals

• Reactivity in Group 1


  Explained in terms of electronic configurations
• Drawing full electron configurations for Li, Na and K

  1. Li

  2. Na

  3. K
• Lithium


  • More shielding between nucleus and outer shells
  • Weaker attraction of nucleus for outer electrons
  • Easier to lose outer electrons
• Down the group


  Reactivity increases
• Lithium, sodium and potassium become more reactive down the group: K > Na > Li
• The pH of the solution formed is alkaline because there is more hydroxide (OH-) being produced
• Common indicators turn blue in alkaline solutions