C1 – Higher – Topic 1 – Key concepts – Ionic Bonding Q1. Calcium oxide is an ionic solid.

Figure 5 shows the arrangement of electrons in a calcium atom and in an oxygen atom.

Figure 5

Complete Figure 6 to show the electronic configurations and charges of the calcium ion and the oxide ion.

Use dots to show the electrons originally in the calcium atom and crosses to show the electrons originally in the oxygen atom.

(3)

charge on ion .................................................. charge on ion ..................................................

Figure 6 (Total for question = 3 marks)

Q2.

Calcium nitrate, Ca(NO3)2, is an ionic solid.

State the formulae of the ions in calcium nitrate. (2)

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Q3.

Answer the question with a cross in the box you think is correct . If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .

When copper sulfate solution reacts with sodium hydroxide solution, a precipitate of copper hydroxide and a solution of sodium sulfate are formed.

The equation is

CuSO4 + 2NaOH → Cu(OH)2 + Na2SO4

The formula of the sodium ion is Na+.

What is the formula of the sulfate ion? (1)

A SO4+

B SO4−

C SO42+

D SO42− (Total for question = 1 mark)

Q4.

Answer the question with a cross in the box you think is correct . If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .

Magnesium has an atomic number of 12.

Which line in the table shows the correct numbers of protons, neutrons and electrons in a positively charged magnesium ion?

(1)

(Total for question = 1 mark)

Q5. (a) Sodium chloride is a metal chloride which is soluble in cold water.

(i) Give the name of a metal chloride which is insoluble in cold water. Put a cross ( ) in the box next to your answer.

(1) A copper chloride B lead chloride C magnesium chloride

D potassium chloride

(ii) Sodium chloride has a melting point of 801 °C. Explain why the melting point of sodium chloride is high.

(2)

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.............................................................................................................................................. (iii) Describe how you would test for the presence of chloride ions in a solution of sodium chloride.

(3)

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.............................................................................................................................................. *(b) Magnesium has an electronic configuration of 2.8.2. Oxygen has an electronic configuration of 2.6.

Explain, in terms of their electronic configurations, how magnesium and oxygen atoms react to form the ionic compound magnesium oxide, MgO, and include a description of the structure of solid magnesium oxide.

(6)

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Q6.

Particles and formulae

(a) Atoms contain protons, neutrons and electrons. Complete the table to show the relative mass and relative charge of each particle and its position in an atom.

(3)

(b) Complete the sentence by putting a cross ( ) in the box next to your answer.

An atom of an element always contains (1)

A more protons than neutrons

B equal numbers of protons and neutrons

C more electrons than protons

D equal numbers of protons and electrons

(c) The symbols for some atoms are given in the box

From the box, choose the symbol of (i) an atom in group 2 of the periodic table

(1)

........................................................... (ii) an atom that readily forms an ion with a charge of 2−

(1)

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(d) The formula of aluminium nitrate is Al(NO3)3

(i) State the total number of atoms in the formula Al(NO3)3

(1)

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(ii) What is the most likely formula of aluminium nitride?

Put a cross ( ) in the box next to your answer. (1)

A Al(NO3)2 B AlNO3 C AlNO2 D AlN

(Total for question = 8 marks)

Q7. When copper sulfate solution reacts with sodium hydroxide solution, a precipitate of copper hydroxide and a solution of sodium sulfate are formed.

The equation is

CuSO4 + 2NaOH → Cu(OH)2 + Na2SO4

Copper ions, Cu2+, react with hydroxide ions to form copper hydroxide.

Write the ionic equation for this reaction. (2)

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Q8. * Magnesium has an electronic configuration of 2.8.2. Oxygen has an electronic configuration of 2.6. Explain, in terms of their electronic configurations, how magnesium and oxygen atoms react to form the ionic compound magnesium oxide, MgO, and include a description of the structure of solid magnesium oxide.

(6)

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Q9. * Explain how, in this reaction, magnesium and oxygen atoms form a solid that has a high melting point.

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Q10. The table shows the number of electrons, neutrons and protons in particles P, Q, R, S, T and V.

(i) Which particle is a negatively charged ion?

Put a cross ( ) in the box next to your answer. (1)

A P B S C T D V

(ii) Which particles are atoms of metals? Put a cross ( ) in the box next to your answer.

(1) A P and R B Q and R C Q and S D Q, S and V

Mark Scheme Q1.

Q2.

Q3.

Q4.

Q5.

Answer Acceptable answers

Mark

(a)(i) B lead chloride (1) (a)(ii) An explanation

linking two of • strong (electrostatic) forces of attraction • between oppositely charged ions • so requires lot of heat/energy to overcome forces/break bonds

Any reference to molecules/molecular/intermolecul ar/covalent scores 0 marks strong (ionic) bonds positive and negative ions reject charged atoms for this mark ignore hard to melt/high temperature needed

(2) (a)(iii) A description

including • M1 add (dilute) nitric acid • M2 add silver nitrate (solution) • M3 forms white ppt/solid

Accept correct formulae If use any other acid can score M2 and M3 dependent on use of silver nitrate Alternative method: Electrolyse (1) Chlorine formed (1) Bleaches litmus/pH paper (1) Ignore smell (3)

Indicative Content Mark

QWC *(b) A description including some of the following points ion formation • magnesium atoms lose electrons • each magnesium atom loses two electrons • to acquire full outer shell • magnesium (configuration) becomes 2.8 • forms Mg2+ ion • electrons transferred to oxygen atoms • oxygen atoms gain electrons • each oxygen atom gains two electrons • oxygen (configuration) becomes 2.8 • to acquire full outer shell • forms O2- ionstructure • magnesium ions attract oxide ions • due to opposite charges • ions pack close together • ratio of ions 1: 1 • ions arranged in lattice • giant (ionic) (structure)diagram can be credited for any points (6)

Level 0 No rewardable content 1 1 - 2

• a limited description e.g. magnesium atoms lose electrons and oxygen atoms gain electrons e.g. magnesium oxide is a giant structure • the answer communicates ideas using simple language and uses limited scientific terminology • spelling, punctuation and grammar are used with limited accuracy

2 3 - 4 • a simple description e.g. magnesium atoms lose two electrons to form positive ions and oxygen atoms gain two electrons to form negative ions • e.g. magnesium atoms lose electrons and oxygen atoms gain electrons and magnesium oxide is a giant structure • the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately • spelling, punctuation and grammar are used with some accuracy

3 5 - 6 • a detailed description e.g. each magnesium atom transfers two electrons to an oxygen atom and the opposite charged ions (Mg2+ /O 2-) formed attract each other to form a giant (ionic) lattice • the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately • spelling, punctuation and grammar are used with few errors

Q6.

Q7.

Q8.

Indicative Content Mark

QWC * A description including some of the following points ion formation • magnesium atoms lose electrons • each magnesium atom loses two electrons • to acquire full outer shell • magnesium (configuration) becomes 2.8 • forms Mg2+ ion • electrons transferred to oxygen atoms • oxygen atoms gain electrons • each oxygen atom gains two electrons • oxygen (configuration) becomes 2.8 • to acquire full outer shell • forms O2- ionstructure • magnesium ions attract oxide ions • due to opposite charges • ions pack close together • ratio of ions 1: 1 • ions arranged in lattice • giant (ionic) (structure)diagram can be credited for (6)

any points Level 0 No rewardable content 1 1 - 2

• a limited description e.g. magnesium atoms lose electrons and oxygen atoms gain electrons e.g. magnesium oxide is a giant structure • the answer communicates ideas using simple language and uses limited scientific terminology • spelling, punctuation and grammar are used with limited accuracy

2 3 - 4 • a simple description e.g. magnesium atoms lose two electrons to form positive ions and oxygen atoms gain two electrons to form negative ions • e.g. magnesium atoms lose electrons and oxygen atoms gain electrons and magnesium oxide is a giant structure • the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately • spelling, punctuation and grammar are used with some accuracy

3 5 - 6 • a detailed description e.g. each magnesium atom transfers two electrons to an oxygen atom and the opposite charged ions (Mg2+ /O 2-) formed attract each other to form a giant (ionic) lattice • the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately • spelling, punctuation and grammar are used with few errors

Q9.

Q10.

Answer Acceptable answers

Mark

(i) C T (1) (ii) C Q and S (1)