CHAPTER 12: Group VII

• Physical Properties of Group VII Elements
• Reactions of Group VII Elements
• Reactions of Halide Ions
• Uses of Halogens

Learning outcomes:

• describe the colours of, and the trend in volatility of chlorine, bromine and iodine
• interpret the volatility of the elements in terms of van der Waals’ forces
• describe the relative reactivity of the elements as oxidising agents
• describe and explain the reactions of the elements with hydrogen
• (i) describe and explain the relative thermal stabilities of the hydrides
  (ii) interpret these relative stabilities in terms of bond energies.

• describe and explain the reactions of halide ions with
  • aqueous silver ions followed by aqueous ammonia
  • concentrated sulfuric acid
• outline a method for the manufacture of chlorine from brine by a diaphragm cell
• describe and interpret in terms of changes of oxidation number the reaction of chlorine with cold, and with hot, aqueous sodium hydroxide
• explain the use of chlorine in water purification
• state the industrial importance and environmental significance of the halogens and their compounds (e.g. for bleaches, PVC, halogenated hydrocarbons as solvents, refrigerants and in aerosols).