8.2 Halogens Flashcards
What do halogens exist as?
Diatomic molecules
What happens to the boiling point of elements in group 7 as you go down the group?
It increases
Why does the bpt. increases as you go down group 7?
There is:
more electrons
stronger london forces
more energy is required to break the intermolecular forces
so bpt. increases
What is the most common reaction of halogens?
Redox
What type of agent are halogens?
An oxidising agent
What is added to tell bromine and iodine apart in water?
Cyclohexane
What colour is bromine in cyclohexane?
Orange
What colour is iodine in cyclohexane?
Violet
What does chlorine react with?
Reacts with bromine and iodine
What does Bromine react with?
Chlorine, orange colour is formed due to the formation of Br2
What does Iodine react with?
No reactions with chlorine and bromine
What is the trend in reactivity down group 7?
It decreases
Why does reactivity decrease down group 7?
Atomic radius increases
More inner shells so more shielding
Less nuclear attraction to capture an electron from another species
Reactivity decreases
What is disproportionation?
A redox reaction in which the same element is both oxidised and reduced.
What is a benefit and risk of chlorine use?
Ensures water is fit to drink by killing bacteria.
It is a toxic gas.
