Group 7 Elements

• what colour is Fluorine?

  yellow
• what colour is chlorine?

  green
• what colour is bromine?

  orange
• what colour is iodine?

  grey
• what state is fluorine?

  gas
• what state is chlorine?

  gas
• what state is bromine?

  liquid
• what state is iodine?

  solid
• what are they called?

  Halogens
• what are they known as?

  diatomic molecules
• Definition of diatomic molecules?

  2 atoms joined by a single covalent bond
• what happens to the melting and boiling point as you go down the group?

  increases due to the increased strength of London Dispersion Forces and the volatility decreases
• what happens to the reactivity as you go down the group?

  decreases due to the atomic radius increasing and shielded more so easier to remove an electron, they are also reduced, and less oxidising as you go down
• what is the test for halides?

  add dilute nitric acid then silver nitrate, and possibly ammonia solution
• what is the precipitate for chloride?

  white
• what is the precipitate for bromide?

  cream
• what is the precipitate for iodide?

  yellow
• why add ammonia solution?


  as each silver halide has a different solubility in ammonia- the larger the ion the more difficult it is to dissolve