The elements of Group 7 – chlorine, bromine and iodine
three of the halogens: chlorine (a green gas), bromine (a orange brown liquid), iodine (a grey solid)
Group 17 ( used to be group 7) contains a set of non-metals known collectively as The Halogens.
Like many families, the members of Halogen family have a number of similarities to each other. However, they also have some very important differences.
Activity 1: Ferocious Fluorine
This video shows a range of elements being mixed with fluorine gas. No heat is supplied! Watch each reactions in turn.
- Write an equation for each reaction.
- Calculate the % mass change which would take place in each reaction.
Activity 2. Comparing the halogens
The main uses of Chlorine
Bromine is unusual as it is one of only three elements that are liquid at room temperature and pressure.
Halogen displacement reactions
This video shows how the reactivity of the halogens changes down the group.
A solution of a halogen ( Cl2 , Br2 or I2 ) is added to a solution of halide (Cl -, Br - , I-). If the halogen is more reactive than the halide it will displace the halide from the solution and there will be a colour change as a result.