4.5 Elements in group 17

• Name the firsst four members of group 17, their symbol and electron arrangemetn

  1. Fluorine, F 2.7
  2. Chlorine, Cl 2.8.7
  3. Bromine, Br 2.8.18.7
  4. Iodine, I 2.8.18.18.7
• List the physical properties of group 17 for each element (there're 4)

  1. Fluorine - yellow gas
  2. Chlorine - greenish yellow gas
  3. Bromine - brown liquid
  4. Iodine - purple black solid
• Lis the physical properties of group 17 (hint: similar to G18)

  • does not conduct electricity
  • low boiling point
• why does group 17 have a low boiling point?

  Halogens are attracted by weak Vanderwaals force. Only little heat needed to overcome force of attraction
• What happens when moving down group 17?

  • atomic size increases
  • density increases
  • boiling point increases
• Why does the atomic size increase when going down group 17?

  More shells are occupied with electrons
• Why does density increase when going down group 17?

  Because mass increases faster than volume
• Why does the boiling point increase when going down group 17?

  Moving down the group, atomic size will increase Vanderwaals force will become stronger, more heat is needed to overcome force of attraction
• List down the reactivity of group 17, when going down the group

  • size of atom increases
  • force of attraction between nucleus and valence electron become weaker
• What happens when size of atom increases (reactivity)

  Valence electron gets further away from nucleus
• What happens to the reactivity when the force of attraction between nucleus and valence electron become weaker?

  Harder to receive / pull / attract electron, reactivity decreases
• What are the chemical properties of group 17 when reacted with water?

  Cl2 + H2O -> HCl + HClO

  F2 + H2O -> HF + HFO

  Br2 + H2O -> HBr + HBrO

  I2 + H2O -> HI + HIO