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 | Melting point (∘C^\circ\text{C}∘C) | Order of reactivity |
|---|---|---|---|---|
| Fluorine | F2\text{F}_2F2 | gas | -220 | most reactive |
| Chlorine | Cl2\text{Cl}_2Cl2 | gas | -101 | ↓\quad\downarrow↓ |
| Bromine | Br2\text{Br}_2Br2 | ........................ | -7 | ↓\quad\downarrow↓ |
| Iodine | I2\text{I}_2I2 | solid | ........................ | least reactive |
Complete the table by predicting the state of bromine at room temperature and the melting point of iodine. 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:
chlorine+potassium bromide→potassium chloride+bromine \text{chlorine} + \text{potassium bromide} \rightarrow \text{potassium chloride} + \text{bromine} chlorine+potassium bromide→potassium chloride+bromine Cl2+2KBr→2KCl+Br2 \text{Cl}_2 + 2\text{KBr} \rightarrow 2\text{KCl} + \text{Br}_2 Cl2+2KBr→2KCl+Br2(i) Complete the word equation:
chlorine+potassium iodide→........................+........................ \text{chlorine} + \text{potassium iodide} \rightarrow \text{........................} + \text{........................} chlorine+potassium iodide→........................+........................(ii) There is no reaction between bromine and potassium chloride. Explain why.
(iii) Fluorine reacts with sodium chloride. Sodium fluoride and chlorine are produced. Write the balanced symbol equation for this reaction.
(i) Lithium 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 lithium reacting with?
(ii) Potassium is another Group 1 metal. Potassium reacts in a very similar way to lithium. Explain why, using ideas about atomic structure.