Group 7 Flashcards
What do halogens refer to
The atoms or molecules of group 7 elements
What do halides refer to
The ions of group 7 elements
What are the colours of chlorine in water and cyclohexane
Pale green
Pale green
What are the colours of bromine in water and cyclohexane
Orange
Orange
What are the colours of iodine in water and cyclohexane
Brown
Violet
Explain why the halogen in more soluble in the cyclohexane layer
Halogen is a non polar molecule and cyclohexane is a non polar solvent so the non polar molecule is more soluble than the non polar solvent
In terms of forces and particles how do you explain the trend of halogens
Chlorine is a gas bromine liquid iodine solid because boiling point increases down the group
There are induced dipole dipole forces between halogen molecules
Iodine has more electrons than bromine which has more electrons than chlorine
The more electrons in the molecule the stronger the induced dipole dipole
Therefore the more energy required to break the forces
What agents do group 7 act as
Oxidising agents causing the other species to lose electrons because they are msot likely to undergo reduction by gaining electrons to complete its outer shell
What is the trend of reactivity down group 7
As atomic radius increases shielding increases which outweigh the increase in nucleur charge Therefore the nucleur charge decreases
So the ability to attract an electron from another species decreases
This means reactivity decreases down the group
What are halogen displacement reactions
Redox reactions between a halogen and a halide
If the halogen is the stronger oxidising agent than the halide the halide will be oxidised and the halogen reduced
If the halide is the stronger oxidising agent no reaction will occur
Why does the boiling point of the halogens increase down group 7
London forces between the molecules
the number of electrons increase down the group so they are stronger
So more energy is required to break them
What are the reaction equations
Cl2 + 2Br- —> Br2+ 2Cl-
Cl2+ 2I- —> I2+ 2Cl-
Br2 + 2I- —> I2+ 2Br-
What are the reactions between Cl2 and Br2 with I-
Orange or brown solution or purple in organic
What is the reaction of Cl2 with Br-
yellow solution or orange in organic
What happens when chlorine is added to water
It produces HClO + HCl
And kills bacteria
Bacteria is killed by the chlorate ion
