This question is about elements in the Periodic Table.
Look at the table showing some properties of Group 7 elements:
| Element | Molecular formula | State at room temperature | Boiling point (∘C^\circ\text{C}∘C) | Order of reactivity |
|---|---|---|---|---|
| Chlorine | Cl2\text{Cl}_2Cl2 | gas | -34 | most reactive |
| Bromine | Br2\text{Br}_2Br2 | liquid | 59 | ↓\quad\downarrow↓ |
| Iodine | I2\text{I}_2I2 | ........................ | 184 | ↓\quad\downarrow↓ |
| Astatine | At2\text{At}_2At2 | solid | ........................ | least reactive |
Complete the table by predicting the state of iodine at room temperature and the boiling point of astatine. Use the trends down the group to help you.
The Group 7 elements are listed in the table in order of reactivity. The equations below show a displacement reaction:
bromine+sodium iodide→sodium bromide+iodine \text{bromine} + \text{sodium iodide} \rightarrow \text{sodium bromide} + \text{iodine} bromine+sodium iodide→sodium bromide+iodine Br2+2NaI→2NaBr+I2 \text{Br}_2 + 2\text{NaI} \rightarrow 2\text{NaBr} + \text{I}_2 Br2+2NaI→2NaBr+I2(i) Complete the word equation:
bromine+potassium iodide→........................+........................ \text{bromine} + \text{potassium iodide} \rightarrow \text{........................} + \text{........................} bromine+potassium iodide→........................+........................(ii) There is no reaction between iodine and sodium bromide. Explain why.
(iii) Fluorine reacts with potassium bromide. Potassium fluoride and bromine are produced. Write the balanced symbol equation for this reaction.
(i) Sodium is a Group 1 metal. It is stored under oil in a sealed container because it is very reactive. What does the oil stop the sodium reacting with?
(ii) Caesium is another Group 1 metal. Caesium reacts in a very similar way to sodium. Explain why, using ideas about atomic structure.