Exam code: 4XSD1
The table below shows the properties of four substances, W, X, Y and Z.
Substance
| Melting point / o C | Boiling point / o C | Conducts electricity when | |
solid | liquid | |||
W | 3410 | 5930 | yes | yes |
X | 801 | 1413 | no | yes |
Y | 3550 | 4830 | no | no |
Z | -91 | 98 | no | no |
Use the information in the table to identify the substance that is an ionic compound.
substance W
substance X
substance Y
substance Z
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Which of the statements describes ionic bonding?
Electrostatic attraction between atoms
Electrostatic attraction between positively charged particles and delocalised electrons
Electrostatic attraction between oppositely charged ions
Electrostatic attraction between the nuclei of two atoms and a shared pair of electrons
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This question is about lithium and chlorine. Which group of the Periodic Table is chlorine in?
Lithium reacts with chlorine to produce lithium chloride.
lithium + chlorine → lithium chloride
The diagram shows how the reaction happens.
Only the outer electrons are shown.
Use the words in the boxes to complete the sentences:
gaining | sharing | positive | group 1 | negative |
covalent | losing | group 0 | electrostatic | neutral |
A lithium atom becomes an ion by ............................................... one electron.
A lithium ion has a ............................................... charge.
The lithium ion now has the electronic structure of a ............................................... element.
The ions in lithium chloride are held together by strong ............................................... forces.
Why do lithium and chlorine react in this way?
Magnesium and bromine will form an ionic compound, like lithium and chlorine.
What is the formula of the ionic compound formed from magnesium and bromine?
MgBr
MgBr2
Mg2Br
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Sodium chloride is an ionic compound which is soluble in water. Sodium ions and chloride ions bond together forming an ionic lattice.
i) Explain how a sodium atom becomes a sodium ion.
[2]
ii) Explain how a chlorine atom becomes a chloride ion.
[2]
Which of the following explains why sodium fluoride is soluble in water?
Both ionic compounds and water are polar substances
Ionic compounds have weak bonds
Water has weak bonds
Sodium fluoride has a melting point of 993 °C. Why does sodium fluoride have a high melting point?
The electrons and positive ions attract strongly
The covalent bonds between the ions are strong
There are strong bonds between the positively and negatively charged ions
Sodium fluoride can conduct electricity when either molten or in solution. Why can sodium fluoride only conduct electricity when molten or in solution?
Electrons can move and carry a charge
Ions can move and carry a charge
Electrons can flow throughout the ionic lattice
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This question is about sodium oxide, Na2O
The diagram shows the electronic configuration of atoms of sodium and oxygen.
 |  |
Sodium | Oxygen |
Describe the changes in the electronic configuration of the atoms of sodium and oxygen to form the ions in sodium oxide.
Calculate the relative formula mass (Mr) of sodium oxide, Na2O, using information from the Periodic Table.
Mr = ..............................
Explain why solid sodium oxide does not conduct electricity.
Give a test to show that sodium oxide contains sodium ions.
When sodium oxide is heated it reacts to form sodium metal and sodium peroxide, Na2O2
Complete the equation for this reaction.
Na2O →
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What is the formula of potassium sulfate?
K2(SO4)2
K(SO4)2
K2SO4
KSO4
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The formation of ions and covalent bonds involves electrons. The table gives the electronic configurations of atoms of hydrogen, lithium and chlorine.
Element | Electronic configuration of atom |
hydrogen | 1 |
lithium | 2.1 |
chlorine | 2.8.7 |
Describe the different roles of electrons in the formation of
ions in lithium chloride
covalent bonds in hydrogen chloride
Explain why lithium chloride has a higher melting point than hydrogen chloride.
Refer to structure and bonding in your answer.
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Which of the following dot-and-cross diagrams shows the correct arrangement of electrons in lithium sulfide?
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The diagram shows the electronic configurations of an atom of lithium and an atom of oxygen.
Which statement is not correct about the changes in electronic configuration that occur when lithium and oxygen react to form lithium oxide, Li2O?
Two lithium atoms each lose one electron
One oxygen atom gains 2 electrons
A lithium ion has an electronic configuration of 2
An oxide ion has an electronic configuration of 2.6
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This question is about ionic compounds.
The table shows the formulae of some positive and negative ions, and the formulae of some compounds containing these ions.
Mg2+ | Al3+ | NH4+ | |
S2- | MgS | Al2S3 | |
NO3- | Al(NO3)3 | NH4NO3 | |
CO32- | MgCO3 | (NH4)2CO3 |
i) Complete the table by giving the three missing formulae.
[3]
ii) Give the name of the compound with the formula NH4NO3
[1]
Sodium oxide, Na2O, is an ionic compound. The sodium and oxide ions are held together by ionic bonds.
i) State the meaning of the term ionic bond.
[2]
ii) The diagram shows the arrangement of the electrons in a sodium atom and in an oxygen atom.
Draw diagrams in the boxes to show the arrangement of the electrons in the ions of sodium oxide. Include the charges on the ions.
[3]
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The diagram shows the arrangement of electrons in an atom of calcium and in an atom of chlorine.
Describe, in terms of electrons, what happens when calcium reacts with chlorine to form the ionic compound calcium chloride, CaCl2
Describe tests to show that an aqueous solution of calcium chloride contains calcium ions and chloride ions.
Solid calcium chloride does not conduct electricity. Aqueous solutions of calcium chloride do conduct electricity. A student uses this method to investigate how the conductivity of a solution changes when calcium chloride is dissolved in pure water.
Step 1 add 100 cm3 of pure water to a beaker
Step 2 add one spatula of solid calcium chloride to the beaker
Step 3 stir the solution
Step 4 measure the conductivity of the solution
Step 5 repeat until nine spatulas of solid calcium chloride have been added
The table shows the student’s results.
Number of spatulas of calcium chloride | Conductivity of solution in arbitrary units |
0 | 0 |
1 | 6 |
2 | 12 |
3 | 12 |
4 | 24 |
5 | 30 |
6 | 36 |
7 | 36 |
8 | 36 |
9 | 36 |
i) Plot the results on the grid and draw two straight lines of best fit. Ignore the anomalous result.
[3]
ii) State the trend shown on the graph for the first six spatulas of calcium chloride.
[1]
iii) Suggest an error the student could have made to cause the anomalous result.
[1]
Describe another way to make solid calcium chloride conduct electricity.
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The diagram shows how the electrons are arranged in an atom of sulfur. Sulfur can form both covalent and ionic compounds.
The electronic configuration of a sodium atom is 2.8.1 Sodium sulfide, Na2S, is an ionic compound formed when sodium reacts with sulfur.
Describe, in terms of electrons, what happens when sodium sulfide is formed in this reaction.
Draw a dot-and-cross diagram to show the bonding in sodium sulfide.
Sodium sulfide is a water-soluble compound. When hydrogen sulfide gas is bubbled through sodium hydroxide it will form sodium sulfide and water. Explain why the melting point of hydrogen sulfide is lower than the melting point of sodium sulfide.
Write a balanced symbol equation including state symbols for the reaction occurring in part c).
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This question is about chemical bonds.
Aluminium and chlorine react to form aluminium chloride.
Write the balanced symbol equation for the reaction.
Include state symbols.
Describe, in terms of electron arrangement, the type of bonding in a molecule of chlorine.
Describe, in terms of electron arrangement, the type of bonding in the compound aluminium chloride.
Explain why molten aluminium chloride can conduct electricity.
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