Reactions of the halogens
3 marks · EasyThe table below shows information about the appearance and melting points of chlorine, bromine, and iodine. Some data is missing.
| Halogen | Colour at room temperature | Physical state at room temperature | Melting point (°C) |
|---|---|---|---|
| Chlorine | Pale green | Gas | -101 |
| Bromine | Liquid | -7 | |
| Iodine | Grey-black | 114 |
Complete the table: (i) the colour of bromine at room temperature, and (ii) the physical state of iodine at room temperature.
Based on the table, describe the trend in melting points down the group.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) Bromine colour: red-brown; Iodine physical state: solid · must show Red-brown for bromine's colour, Solid for iodine's state
(b) Melting point increases down the group. · must show Correct trend: increases
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Gives 'red-brown' as colour of bromine at room temperature.
B1 (a) · 1 mark · Gives 'solid' as physical state of iodine at room temperature.
B1 (b) · 1 mark · States that melting point increases down the group.
Worked solution
| Halogen | Colour at room temperature | Physical state at room temperature | Melting point (°C) |
|---|---|---|---|
| Chlorine | Pale green | Gas | -101 |
| Bromine | Red-brown | Liquid | -7 |
| Iodine | Grey-black | Solid | 114 |
The melting point increases as you go down the group from chlorine to bromine to iodine.