group 1- Alkali Metals

• group 1- alkali metals

  lithium

  sodium

  potassium

  rubidium

  caesium

  down the group:

  mp & bp decreases

  density increases

  more reactive- outer electro is further from nucleus, less strongly held & easier to remove
• react w water making an alkali

  reaction w water:

  all float- low density

  all make alkali solution of ph 8-14

  group 1 metal + water -> metal hydroxide + hydrogen
• lithium- slowly moves over the surface, bubbles of gas
• sodium- moves quickly as a white ball over the surface, orange/yellow spark and bubbles of gas
• potassium- moves very quickly, lilac flame, bubbles of gas, explode at the end due to rapid release of energy & gas
• reaction w oxygen

  all react w oxygen to produce a metal oxide & characteristic flame

  lithium- red

  sodium- orange/yellow

  potassium- lilac 


  metal + oxygen-> metal

  x + O -> x(little 2) O