This question is about the Group 7 elements, the halogens.
The table shows some information about four halogens.
| Halogen | Melting point (°C) | Boiling point (°C) | State at room temperature |
|---|---|---|---|
| fluorine | −220 | −188 | gas |
| chlorine | −101 | −34 | ? |
| bromine | −7 | 59 | liquid |
| iodine | 114 | 184 | solid |
What is the state of chlorine at room temperature (20 °C)?
Astatine is below iodine in Group 7.
Predict the state of astatine at room temperature.
Explain your answer. Use the information in the table.
A student adds solutions of three halogens to solutions of three potassium halides.
The table shows the results.
| Halogen solution added | Potassium chloride solution | Potassium bromide solution | Potassium iodide solution |
|---|---|---|---|
| chlorine | not done | orange solution forms | brown solution forms |
| bromine | no reaction | not done | brown solution forms |
| iodine | no reaction | no reaction | not done |
Use the results to put chlorine, bromine and iodine in order of reactivity.
Start with the most reactive.
Complete the word equation for the reaction between chlorine and potassium bromide.
chlorine + potassium bromide → ...... + ......
Explain why bromine does not react with potassium chloride solution.
The diagrams show the electronic structures of a fluorine atom and a chlorine atom.
image:4.1_image1.png
The halogens become less reactive down Group 7.
Explain why. Use the diagrams and ideas about electrons.
60 exam-style questions on OCR GCSE Chemistry 4.1 Predicting chemical reactions, covering 4.1.1 Properties and trends in Groups 1, 7 and 0, 4.1.2 Properties of the transition metals, 4.1.3 Reactivity predicted from position in the Periodic Table, and 4.1.4 Reactivity of metals and the reactivity series. Each one has a worked solution and a mark scheme showing where the marks go.