The halogens are a group of non-metal elements. Their molecules are held together by covalent bonds.
The table shows the melting points and boiling points of four halogens.
| Halogen | Formula | Melting point in °C | Boiling point in °C |
|---|---|---|---|
| fluorine | F2\mathrm{F_{2}}F2 | −220 | −188 |
| chlorine | Cl2\mathrm{Cl_{2}}Cl2 | −101 | −34 |
| bromine | Br2\mathrm{Br_{2}}Br2 | −7 | 59 |
| iodine | I2\mathrm{I_{2}}I2 | 114 | 184 |
Describe the trend in boiling points going down group 7.
Use the data to explain why bromine is a liquid at 25 °C.
A sample of chlorine gas is cooled to −50 °C. State the physical state of chlorine at −50 °C.
Calculate the relative formula mass of an iodine molecule, I2\mathrm{I_{2}}I2. Relative atomic mass: I = 127
Explain why iodine has a higher boiling point than chlorine.
Astatine is below iodine in group 7. Estimate the boiling point of astatine.
41 exam-style questions on Edexcel GCSE Chemistry 7.2 Group 7, covering 7.2.1 Physical properties of the halogens, 7.2.2 Reactions of the halogens, 7.2.3 Relative reactivity and displacement reactions of the halogens, and 7.2.4 Halogen displacement as a redox reaction. Each one has a worked solution and a mark scheme showing where the marks go.