Which element in Group 7 is a solid at room temperature?
☐ | A | fluorine | |
☐ | B | chlorine | |
☐ | C | bromine | |
☐ | D | iodine |
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Which element in Group 7 is a solid at room temperature?
☐ | A | fluorine | |
☐ | B | chlorine | |
☐ | C | bromine | |
☐ | D | iodine |
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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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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.
Name a halogen that is a solid at room temperature.
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.
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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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 |
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.
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).
(1)
(1)
Sodium, Na, reacts with chlorine. A white solid is made.
(1)
(2)
........ Na + ........ Cl2 → ................
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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?
Which of the elements from Table 1 would be a gas at room temperature?
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 |
Fluorine has an atomic number of 9.
Draw a diagram to show the electron arrangement of an atom of fluorine.
Fluorine undergoes similar reactions to chlorine and bromine.
Explain why.
Bromine can react with potassium iodide.
Complete the word equation for the reaction.
Choose the correct words from the box below.
|
bromine + potassium iodide → ____________________ + ____________________
Why does bromine not react with potassium chloride solution?
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This question is about some of the halogens and their compounds.
☐ | A | astatine | |
☐ | B | bromine | |
☐ | C | chlorine | |
☐ | D | iodine |
☐ | A | astatine | |
☐ | B | bromine | |
☐ | C | chlorine | |
☐ | D | iodine |
☐ | A | astatine | |
☐ | B | bromine | |
☐ | C | chlorine | |
☐ | D | iodine |
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.
(2)
(1)
(1)
A technician sees an unlabelled bottle containing a liquid.
He knows that the liquid is a solution of one of these compounds.
Describe chemical tests that the technician could use to identify the compound in the solution.
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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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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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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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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.
Chlorine 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 = .........................
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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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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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 |
Bromine has two isotopes with mass numbers 79 and 81
(3)
relative atomic mass = ..............................................................
A student investigates the reactivity of some halogens.
She uses these solutions of halogens and their halides.
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 |
(3)
(1)
Br2 (aq) + 2I− (aq) → I2 (aq) + 2Br− (aq)
(2)
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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 ....................................
An aqueous solution of halogen Y2 is orange.
This solution is decolourised when it reacts with an alkene.
Deduce the identity of halogen Y2.
The table shows some physical properties of the halogens.
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)
☐ | 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 |
A teacher uses this apparatus to demonstrate the reaction between chlorine gas and iron wool. The teacher does the reaction in a fume cupboard.
(1)
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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 |
☐ | A | 0 | |
☐ | B | 1 | |
☐ | C | 2 | |
☐ | D | 3 |
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)
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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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: ____________________
Explain why the boiling point of the Group 7 elements increases as you go down the group as shown in Table 1.
The halogens all react with hydrogen to form the corresponding hydrogen halide.
Explain why the halogens all react in a similar way.
Predict and explain the difference in the rate of the reaction between hydrogen with chlorine and between hydrogen and iodine.
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Chorine is a halogen.
Chlorine reacts with aqueous potassium iodide to form aqueous potassium chloride and iodine.
(2)
(1)
This reaction is a redox reaction.
Explain, using half equations, what is being oxidised and what is being reduced.
Explain, in terms of their electronic configuration, why chlorine is more reactive than iodine.
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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