Section+2c

back to IGCSE chemistry **The group 7 elements - chlorine, bromine and iodine**

You will be assessed on your ability to
2.9 recall the colours and physical states of the elements at room temperature 2.10 make predictions about the properties of other halogens in this group 2.11 understand the difference between hydrogen chloride gas and hydrochloric acid 2.12 explain,in terms of dissociation, why hydrogen chloride is acidic in water but not in methylbenzene 2.13 recall the relative reactivities of the elements in Group 7 2.14 describe experiments to show that a more reactive halogen will displace a less reactive halogen from a solution of one of its salts 2.15 understand these displacement reactions as redox reactions = Section notes =

= Investigations = [|Halogens reacting with iron] = Resources = **Textbook** page 105 - 109

Animations
Watch the animation below which shows displacement reactions of halogens. [|displacement simulation]

When a colour change occurs a reaction takes place because the halogen is displacing a halide from its compound 1. Design your own results table and record your observations i.e. colour changes. 2. For each of the displacement reactions write a word equation, a balanced symbol equation and an ionic equation. 3. Which halogen is the most reactive?

[|video clip of a displacement]