11 mark
Which element in Group 7 is a solid at room temperature?
| ☐ | A | fluorine | |
| ☐ | B | chlorine | |
| ☐ | C | bromine | |
| ☐ | D | iodine |
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2.2 Group 7 (Halogens)
21 mark
This table gives information about some of the halogens.
| Halogen | Physical state at room temperature | Colour |
| fluorine | gas | |
| chlorine | pale green | |
| bromine | liquid | red-brown |
What is the correct missing physical state and colour?
| Physical state at room temperature | Colour | |||
| ☐ | A | gas | colourless | |
| ☐ | B | liquid | colourless | |
| ☐ | C | gas | pale yellow | |
| ☐ | D | liquid | pale yellow |
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3a1 mark
Astatine, bromine, chlorine, fluorine and iodine are all halogens. They are found in Group 7 of the Periodic Table.
Predict which halogen has the lightest colour.
3b1 mark
Name a halogen that is a solid at room temperature.
3c3 marks
Bromine can be obtained from the bromide ions in sea water. Chlorine is bubbled into sea water. The chlorine oxidises the bromide ions to bromine atoms. The bromine atoms then form bromine molecules.
i)
Complete the equation to show how bromine atoms are formed from bromide ions.
Cl2 + ..................... Br− → 2Cl− + ..................... Br
(1)
ii)
State why this reaction is described as the oxidation of bromide ions.
(1)
iii)
Write an equation to show how bromine atoms form bromine molecules.
(1)
3d2 marks
Boron and fluorine form a covalent compound that has the molecular formula BF3
Draw a dot-and-cross diagram to show the arrangement of the outer electrons in a molecule of BF3
Use crosses (×) to represent the outer electrons of boron. Use dots (•) to represent the outer electrons of fluorine.
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4a1 mark
The Group 7 elements are called the halogens.
Table 1 shows information about some of the halogens.
Table 1
| Name | Atomic number | Boiling point (°C) |
Molecular formula |
| Fluorine | 9 | −188 | F2 |
| Chlorine | 17 | −34 | Cl2 |
| Bromine | 35 | 59 | Br2 |
| Iodine | 53 | 184 | I2 |
Which is the most reactive halogen in the table?
| ☐ | A | fluorine | |
| ☐ | B | chlorine | |
| ☐ | C | bromine | |
| ☐ | D | iodine |
4b4 marks
The Group 7 elements exist in different states at room temperature.
Draw one straight line from each Group 7 element to its correct state at room temperature.
4c2 marks
Astatine is also a halogen. It has the atomic symbol At and an atomic number of 85.
Use Table 1 and your answer from part (b).
i)
Predict the state of astatine at room temperature.
(1)
ii)
Predict the boiling point of astatine.
(1)
4d3 marks
Sodium, Na, reacts with chlorine. A white solid is made.
i)
What is the name of this white solid?
(1)
ii)
Complete the balanced symbol equation for this reaction.
(2)
........ Na + ........ Cl2 → ................
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5a1 mark
This question is about Group 7 elements.
Table 1 shows the melting point and boiling point of some Group 7 elements.
Table 1 shows the melting point and boiling point of some Group 7 elements.
Table 1
| Element | Melting point in oC | Boiling point in oC |
| Chlorine | -101 | -25 |
| Bromine | -7 | 59 |
| Iodine | 114 | 184 |
What is the state of bromine at 50 oC?
5b1 mark
Which of the elements from Table 1 would be a gas at room temperature?
5c2 marks
Which two of the following statements is correct about the elements in Group 7?
Tick (✓) two boxes.
| They are metals that exist as molecules of two atoms | |
| They have seven electrons in their outer shell | |
| They are non-metals that exist as molecules of two atoms | |
| They react with metals to form molecular compounds | |
| The reactivity increases down the group |
5d2 marks
Fluorine has an atomic number of 9.
Draw a diagram to show the electron arrangement of an atom of fluorine.
5e2 marks
Fluorine undergoes similar reactions to chlorine and bromine.
Explain why.
5f2 marks
Bromine can react with potassium iodide.
Complete the word equation for the reaction.
Choose the correct words from the box below.
|
bromine + potassium iodide → ____________________ + ____________________
5g1 mark
Why does bromine not react with potassium chloride solution?
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1a2 marks
This question is about the halogens.
The table gives some information about the halogens.
Complete the table by predicting the physical state of astatine at room temperature and the colour of astatine.
| Halogen | Physical state at room temperature | Colour |
| fluorine | gas | yellow |
| chlorine | gas | pale green |
| bromine | liquid | red-brown |
| iodine | solid | grey |
| astatine |
1b
4 marks
4 marksBromine has two isotopes with mass numbers 79 and 81
i)
The relative percentages of each isotope in a sample of bromine are
bromine-79 = 51.0% bromine-81 = 49.0%
Calculate the relative atomic mass of this sample of bromine.
Give your answer to one decimal place.
(3)
relative atomic mass = ..............................................................
ii)
Give a reason why both isotopes of bromine have the same chemical properties.
(1)
1c6 marks
A student investigates the reactivity of some halogens.
She uses these solutions of halogens and their halides.
- bromine, chlorine and iodine
- sodium bromide, sodium chloride and sodium iodide
She adds each halogen solution to each halide solution.
The table shows her results.
| Sodium bromide | Sodium chloride | Sodium iodide | |
| Bromine | no reaction | no reaction | reaction occurs |
| Chlorine | reaction occurs | no reaction | reaction occurs |
| Iodine | no reaction | no reaction | no reaction |
i)
Explain how these results show the order of reactivity of bromine, chlorine and iodine.
(3)
ii)
Suggest why the student does not need to add bromine solution to sodium bromide solution.
(1)
iii)
The ionic equation for the reaction between bromine and sodium iodide is
Br2 (aq) + 2I− (aq) → I2 (aq) + 2Br− (aq)
Explain why this is a redox reaction.
(2)
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2a1 mark
The Group 7 elements are called halogens.
Halogens form compounds called halides.
Three of the halogens are represented by the formulae X2 , Y2 and Z2
Solutions of these halogens are added separately to solutions of sodium halides, NaX, NaY and NaZ.
The table shows whether or not a reaction occurs.
| X2 | Y2 | Z2 | |
| NaX | no | yes | yes |
| NaY | no | no | yes |
| NaZ | no | no | no |
Use the information in the table to deduce the order of reactivity of the halogens X2 , Y2 and Z2
most reactive ...................................
....................................
least reactive ....................................
2b1 mark
An aqueous solution of halogen Y2 is orange.
This solution is decolourised when it reacts with an alkene.
Deduce the identity of halogen Y2.
2c4 marks
The table shows some physical properties of the halogens.
i)
Complete the table by predicting a boiling point for chlorine, the state of fluorine at room temperature and the colour of astatine.
| Halogen | Boiling point in °C | State at room temperature | Colour |
| fluorine | -188 | yellow | |
| chlorine | gas | green | |
| bromine | 59 | liquid | red-brown |
| iodine | sublimes | solid | grey |
| astatine | 337 | solid |
(3)
ii)
Why do the halogens have similar chemical properties?
(1)
| ☐ | A | they are non-metals | |
| ☐ | B | they are molecules | |
| ☐ | C | they have the same number of outer shell electrons | |
| ☐ | D | they are in the same period of the Periodic Table |
2d3 marks
A teacher uses this apparatus to demonstrate the reaction between chlorine gas and iron wool. The teacher does the reaction in a fume cupboard.
i)
Suggest why the teacher does the reaction in a fume cupboard.
(1)
ii)
The product of the reaction between iron and chlorine is iron(III) chloride.
The ions in iron(III) chloride are Fe3+ and Cl−.
The ions in iron(III) chloride are Fe3+ and Cl−.
Use this information to give the chemical equation for this reaction.
(2)
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3a3 marks
his question is about elements in Group 7 and their compounds.
The table gives information about some of these elements.
| Element | Symbol | Melting point | Boiling point in °C |
Colour at room temperature (20 °C) |
| fluorine | F | –220 | –188 | |
| chlorine | Cl | –101 | –35 | pale green |
| bromine | Br | –7 | 59 | red-brown |
| iodine | I | 114 | 184 | grey |
i)
Predict the colour of fluorine at room temperature.
(1)
ii)
How many of the elements in the table are liquids at room temperature (20 °C)?
(1)
| ☐ | A | 0 | |
| ☐ | B | 1 | |
| ☐ | C | 2 | |
| ☐ | D | 3 |
iii)
The element astatine is below iodine in Group 7. Predict the formula of a molecule of astatine.
(1)
3b5 marks
Separate: Chemistry Only
Sea water contains bromide ions.
Bromine can be obtained by bubbling chlorine through a sample of sea water.
The ionic equation for the reaction is
Cl2 (g) + 2Br – (aq) → 2Cl– (aq) + Br2 (aq)
i)
Explain which species acts as an oxidising agent in this reaction.
(2)
ii)
The reaction occurs because chlorine is more reactive than bromine. Bromine is below chlorine in Group 7. Explain the decrease in reactivity from chlorine to bromine.
(3)
3c1 mark
Elements in Group 7 react with elements in Group 1 to form ionic compounds.
Which pair of ions both have the electronic configuration 2.8.8?
| ☐ | A | Li+ and Cl | |
| ☐ | B | K+ and F– | |
| ☐ | C | Li+ and F– | |
| ☐ | D | K+ and Cl– |
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4a2 marks
The halogens are found in Group 7 of the Periodic Table.
Table 1 shows the melting point and boiling point of some of the halogens.
Table 1
| Element | Melting Point in oC | Boiling Point in oC |
| Fluorine | -220 | -188 |
| Chlorine | -101 | -25 |
| Bromine | -7 | 59 |
| Iodine | 114 | 184 |
What is the state of chlorine at -100 oC and at 0 oC?
State at -100 oC: ____________________
State at 0 oC: ____________________
4b3 marks
Explain why the boiling point of the Group 7 elements increases as you go down the group as shown in Table 1.
4c2 marks
The halogens all react with hydrogen to form the corresponding hydrogen halide.
Explain why the halogens all react in a similar way.
4d3 marks
Separate: Chemistry Only
Predict and explain the difference in the rate of the reaction between hydrogen with chlorine and between hydrogen and iodine.
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5a3 marks
Chorine is a halogen.
Chlorine reacts with aqueous potassium iodide to form aqueous potassium chloride and iodine.
i)
Give the balanced symbol equation for this reaction.
(2)
ii)
State what would be seen when this reaction occurs.
(1)
5b4 marks
Separate: Chemistry Only
This reaction is a redox reaction.
Explain, using half equations, what is being oxidised and what is being reduced.
5c3 marks
Separate: Chemistry Only
Explain, in terms of their electronic configuration, why chlorine is more reactive than iodine.
5d3 marks
Chlorine reacts with potassium to form the solid, potassium chloride.
Write the balanced symbol equation for this reaction, including state symbols.
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1a3 marks
This question is about some of the halogens and their compounds.
i)
Which element is a liquid at room temperature?
(1)
| ☐ | A | astatine | |
| ☐ | B | bromine | |
| ☐ | C | chlorine | |
| ☐ | D | iodine |
ii)
Which element has the palest colour?
(1)
| ☐ | A | astatine | |
| ☐ | B | bromine | |
| ☐ | C | chlorine | |
| ☐ | D | iodine |
iii)
Which element is the least reactive?
(1)
| ☐ | A | astatine | |
| ☐ | B | bromine | |
| ☐ | C | chlorine | |
| ☐ | D | iodine |
1b4 marks
A teacher uses displacement reactions to demonstrate the reactivities of some halogens.
She adds solutions of chlorine, bromine and iodine separately to three different sodium halide solutions.
The table shows some of the teacher’s results.
| sodium chloride | sodium bromide | sodium iodide | |
| chlorine solution | not done | solution turns orange | |
| bromine solution | solution stays orange | not done | solution turns brown |
| iodine solution | solution stays brown | not done |
A change in colour of the solution indicates that a reaction has occurred.
i)
Complete the table by predicting the missing results.
(2)
ii)
State why the teacher does not add bromine solution to sodium bromide solution.
(1)
iii)
The word equation for the reaction of bromine with sodium iodide is
bromine + sodium iodide → iodine + sodium bromide
Write a chemical equation for this reaction.
(1)
1c6 marks
A technician sees an unlabelled bottle containing a liquid.
He knows that the liquid is a solution of one of these compounds.
- copper(II) chloride
- copper(II) bromide
- iron(II) chloride
- iron(II) bromide
Describe chemical tests that the technician could use to identify the compound in the solution.
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21 mark
Astatine is found below iodine in Group 7 of the Periodic Table.
What is its formula and state at room temperature?
| Formula | State at room temperature | |||
| ☐ | A | At | gas | |
| ☐ | B | At | solid | |
| ☐ | C | At2 | liquid | |
| ☐ | D | At2 | solid |
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31 mark
The reaction between aqueous chlorine and aqueous potassium bromide results in the formation of an orange solution.
Which is the correct statement about this reaction?
| ☐ | A | Bromine is more reactive than chlorine | |
| ☐ | B | Potassium chloride is responsible for the orange colour | |
| ☐ | C | Chlorine displaces bromine from potassium bromide | |
| ☐ | D | Bromide ions gain electrons from chlorine |
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41 mark
Bromine water is an aqueous solution of bromine which is orange in colour.
What would be seen if bromine water was added to the test tubes in the diagram?
| Test tube 1 | Test tube 2 | Test tube 3 | |||
| ☐ | A | solution stays orange | solution turns brown | solution turns brown | |
| ☐ | B | solution turns pale green | solution stays orange | solution turns colourless | |
| ☐ | C | solution stays orange | solution stays orange | solution turns brown | |
| ☐ | D | solution turns colourless | solution turns colourless | solution turns brown |
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5a2 marks
The table gives some information about the halogens, chlorine, bromine and iodine.
|
Halogen |
Physical state at room temperature |
Colour |
| chlorine | gas | pale green |
| bromine | red-brown | |
| iodine | solid |
Complete the table.
5b3 marks
3 marksChlorine has two isotopes of mass numbers 35 and 37.
The relative percentage of each isotope in a sample of chlorine is
chlorine-35 77.78% chlorine-37 22.22%
Calculate the relative atomic mass of this sample of chlorine. Give your answer to one decimal place.
Relative atomic mass = .........................
5c4 marks
A student is given an aqueous solution of chlorine and an aqueous solution of potassium bromide.
Explain how he can use these two solutions to compare the reactivity of chlorine with the reactivity of bromine.
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61 mark
Separate: Chemistry Only
The ionic equation for the reaction between chlorine and sodium bromide is:
Cl2 (g) + 2Br– (aq) → 2Cl– (aq) + Br2 (aq)
This reaction occurs because chlorine is more reactive than bromine.
Which of the statements explaining why chlorine is more reactive than bromine is not true?
| ☐ | A | chlorine has smaller atoms than bromine | |
| ☐ | B | chlorine atoms gain electrons more easily | |
| ☐ | C | chlorine atoms lose electrons more easily | |
| ☐ | D | chlorine atoms have fewer electron shells than bromine atoms |
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