Reactivity Trends: Group 7 Flashcards
At RTP and pressure what do all halogens exist as?
Diatomic molecules.
Describe and explain the trend in boiling point down group 7.
There are more electrons as you go down the group,
Stronger London Dispersion Forces,
More energy required to break the intermolecular forces,
Boiling point increases.
State the appearance and state of Fluorine, Chlorine, Bromine and Iodine at RTP.
Fluorine: Pale yellow (GAS)
Chlorine: Pale green (GAS)
Bromine: Brown (LIQUID)
Iodine: Black (SOLID)
Since halogens are reduced what agent are they?
Oxidising agent.
When you add a halogen to other halide ions and the halogen is more reactive than the halide ions, what happens?
Reactions takes place, halogen displaces the halide,
Solution changes colour.
What happens when you react Chlorine with Bromide ions?
Chlorine displaces the Bromide ions and Bromine is formed.
ORANGE COLOUR
What happens when Chlorine reacts with Iodide ions?
Chlorine displaces the iodide ions, Iodine formed.
VIOLET COLOUR
What happens when you react Bromine with Iodide ions?
Bromine displaces the iodide ions, Iodine formed.
VIOLET COLOUR
Why does Iodine not react with Chloride or Bromide ions?
Chlorine and Bromine are more reactive than Iodine.
Describe and explain the trend in reactivity down group 7.
Atomic radius increases,
More inner shells, more shielding,
Less nuclear attraction,
Reactivity decreases.
What is disproportionation?
A redox reaction where the same element is both oxidised and reduced.
How can you test for halide ions?
Use silver nitrate.
Aqueous halide ions react with aqueous silver nitrate to form precipitates of silver halides.
