Halogens

• The core Halogens

  • Fluorine
  • Chlorine
  • Bromine
  • Iodine
• The reaction for a swimming pool:

  Cl2 + H2O --> HCl + HOCl
• The reaction for Bleach:

  3Cl2 + 6NaOH --> 5NaCl + NaClO + 3H2O
• Fluorine's Physical Properties:

  • Yellow Gas
  • Very reactive
  • Toxic
• Chlorine's Physical Properties:

  • Green gas
  • Very reactive
  • Toxic
• Bromine's Physical Properties:

  • Orange Liquid
  • Very reactive
  • Toxic
  • Often used a solution in water (Bromine Water)
• Iodine's Physical Properties:

  • Grey crystals
  • Reactive
  • Toxic
  • Easily turns purple on heating
  • Used in solutions as anti-septic
• Group 7 has increasing atomic radius

  • More electron shells
  • Bigger atoms
• Group 7 has decreasing electronegativity

  • Bigger atoms
  • More shielding
  • Weaker attraction between nucleus and electrons in covalent bond
• Group 7 has increasing MP and BP down the group

  • Bigger molecules
  • More vdW forces between molecules
• Group 7 decreases in 1st Ionisation Energy

  • Atoms get bigger
  • More shielding
  • Therefore weaker attraction from nucleus to electron in outer shell