The table gives information about three of the elements in Group 7 of the Periodic Table.
| Element | Atomic number | Relative atomic mass | Electronic configuration | Boiling point in ∘C^\circ\text{C}∘C |
|---|---|---|---|---|
| chlorine | 17 | 35.5 | 2.8.7 | -34 |
| bromine | 35 | 80 | 2.8.18.7 | 59 |
| iodine | 53 | 127 | 2.8.18.18.7 | 184 |
Which information shows that the elements have similar chemical properties? Give a reason for your choice.
The elements in Group 7 show a clear trend (regular pattern) in some of their physical properties. Identify the physical property that shows a clear trend in the table.
The elements also show a clear trend in their chemical properties, such as their reaction with hydrogen.
When bromine gas is mixed with hydrogen gas and heated with a catalyst, it reacts to form hydrogen bromide gas.
Describe a test to show that the gas given off (hydrogen bromide) is acidic.
Complete the equation for the reaction of hydrogen gas with bromine gas to form hydrogen bromide gas by inserting the state symbols.
H2(…… )+Br2(…… )→2HBr(…… ) \text{H}_2(\dots\dots) + \text{Br}_2(\dots\dots) \rightarrow 2\text{HBr}(\dots\dots) H2(……)+Br2(……)→2HBr(……)State and explain the effect that a solution of this gas in water has on blue litmus paper.
State two similarities and two differences between the reactions of chlorine and bromine with hydrogen.
When sodium burns in bromine vapor, it forms sodium bromide (NaBr\text{NaBr}NaBr). Write a chemical equation for this reaction.
When iron reacts with bromine vapor, iron(III) bromide (FeBr3\text{FeBr}_3FeBr3) is formed. Balance the equation to show the formation of iron(III) bromide:
……Fe+……Br2→……FeBr3 \dots\dots\text{Fe} + \dots\dots\text{Br}_2 \rightarrow \dots\dots\text{FeBr}_3 ……Fe+……Br2→……FeBr3
