Group 1: Alkali metals

• All of the metals in group one react vigorously with:

  • water to create an alkaline solution and hydrogen (more bubbles with reaction with water = more vigorous reaction = more reactive alkali metal)

  Metal	Reaction with water
  Lithium	fizzes steadily
  Sodium	melts into a ball then fizzes quickly
  Potassium	gives off sparks and hydrogen burns with a lilac flame

  • oxygen to create an oxide

• Reactivity increases down the group, since it is easier to lose electrons. This is because there is more electron shielding and so decrease in attraction between the positively charged nucleus and the negatively charged outer shells

Group 7: Halogens

• Colors and states of matter of atoms at room temperature:

  • Fluorine: yellow gas

  • Chlorine: yellow-green gas

  • Bromine: orange-brown liquid

  • Iodine: grey-purple solid

  • Astatine: black solid

    • Trends for color and state of matter:

      • Color: becomes darker down the group

      • State of matter: gas → liquid → solid

• Melting and boiling points increase as you go down the group, explaining the change in states of matter

• Reactivity decreases as you go down the group

  • This is because as more outer shells form, the further away the negative electrons are from the positive nucleus so its harder to pull in the new electron

• A more reactive halogen can displace a less reactive in an aqueous solution of its salt

  • e.g. Chlorine + Potassium Bromide → Potassium Chloride + Bromine