1.	The Born-Haber cycle for the formation of sodium chloride from sodium and chlorine may be represented by a series of stages labelled A to F as shown.

(a)	(i)	Write the letters A to F next to the corresponding definition in the table below
definition	letter	DH/kJ mol–1	
1st ionisation energy of sodium		+494	
1st electron affinity of chlorine		–364	
the enthalpy of atomisation of sodium		+109	
the enthalpy of atomisation of chlorine		+121	
the lattice enthalpy of sodium chloride		–770	
the enthalpy of formation of sodium chloride			
(3)
 
(ii)	Calculate the enthalpy of formation of sodium chloride from the data given.

(2)

(b)	The lattice enthalpies can be calculated from theory as well as determined experimentally.
	Experimental DH/kJ mol–1	Theoretical DH/kJ mol–1	
Sodium chloride	–770	–766	
Silver iodide	–889	–778	
 
	Why is the experimental value of the lattice enthalpy of silver iodide (–889kJmol–1) so different from the value calculated theoretically?
...................................................................................................................................
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(2)
 
(c)	Explain the trend in first ionisation energies of the elements of Group 1 in the Periodic Table.
...................................................................................................................................
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(3)
(Total 10 marks)

2.	(a)	(i)	Define the terms:
atomic number ...............................................................................................
......................................................................................................................
mass number .................................................................................................
......................................................................................................................
(2)

(ii)	Identify the particle which contains 11 protons, 12 neutrons and 10 electrons.
......................................................................................................................
(1)
 
(b)	Bromine consists of two isotopes, mass numbers 79 and 81.  A sample of bromine gas, Br2, was examined in a mass spectrometer.  The mass spectrum showing the molecular ions is given below.

(i)	Identify the species responsible for the peak at m/e = 160.
......................................................................................................................
(1)
 
(ii)	Deduce the relative abundances of the two isotopes,

(2)

(c)	Define the term first electron affinity for bromine atoms, illustrating your answer with an equation.
................................................................................................................................
................................................................................................................................
................................................................................................................................
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(3)
 
(d)	The graph showing the variation of the first ionisation energies of the elements neon to potassium is given below.

(i)	Define the term first ionisation energy with reference to neon.
......................................................................................................................
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......................................................................................................................
(2)
 
(ii)	Explain the general trend in the first ionisation energies of the elements sodium to argon.
......................................................................................................................
......................................................................................................................
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(2)

(iii)	Explain why the first ionisation energy of neon is greater than the first ionisation energy of argon.
......................................................................................................................
......................................................................................................................
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(2)
(Total 15 marks)

3.	(a)	The Born-Haber cycle for the formation of sodium chloride is shown below.

	Use the data below to calculate the lattice enthalpy of sodium chloride.

Enthalpy change	Value of the
enthalpy change
/kJ mol–1	
Enthalpy of atomisation of sodium	+109	
1st ionisation energy of sodium	+494	
Enthalpy of formation of sodium chloride	–411	
Enthalpy of atomisation of chlorine	+121	
Electron affinity of chlorine	–364	
(2)
 
(b)	Sodium chloride and magnesium oxide have very similar crystal lattices.  Suggest why the lattice enthalpy of magnesium oxide is very much larger than that of sodium chloride.
................................................................................................................................
................................................................................................................................
................................................................................................................................
................................................................................................................................
(2)
 
(c)	The lattice enthalpy of silver iodide can be calculated but the experimental value does not match the calculated value as well as those for sodium chloride match each other.
Explain why the calculated and experimental values for silver iodide are different.
................................................................................................................................
................................................................................................................................
................................................................................................................................
................................................................................................................................
(2)
(Total 6 marks)

4.	(a)	Boron forms the chloride BCl3. Draw a dot-and-cross diagram for BCl3.

(1)
 
(b)	(i)	Draw the shape of the BCl3 molecule.

(1)
 
(ii)	Explain why BCl3 has this shape.
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
(2)
 
(c)	(i)	The B¾Cl bond is polar due to the different electronegativity of the atoms. Explain what is meant by the term electronegativity.
..........................................................................................................................
..........................................................................................................................

(2)
(ii)	The B¾Cl bond is polar. Explain why BCl3 is not a polar molecule.
..........................................................................................................................
..........................................................................................................................
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(2)
(Total 8 marks)

5.	(a)	(i)	State how a flame test would distinguish between samples of calcium nitrate, Ca(NO3)2 and barium nitrate, Ba(NO3)2.
..........................................................................................................................
..........................................................................................................................
(2)
 
(ii)	Explain the origin of the flame colour.
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
 
(3)
(b)	Write the equation for the action of heat on barium nitrate.
....................................................................................................................................
(2)
 
(c)	(i)	What is meant by the term polarising power as applied to cations?
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
(2)
 
(ii)	Give two factors which affect the polarising power of cations.
..........................................................................................................................
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(2)
 
(iii)	Use this information to explain why it is easier to decompose magnesium nitrate than barium nitrate by heating.
..........................................................................................................................
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(3)
(Total 14 marks)

6.	The formation of magnesium chloride from magnesium and chlorine may be represented by the following Born-Haber cycle: 

(a)	Define the terms:
	Lattice enthalpy.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(3)
 
	Enthalpy of atomisation.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(2)
 
(b)	(i)	Identify on the diagram the chance representing the enthalpy of atomisation of magnesium.
(1)
 
(ii)	Use the data below to calculate the first electron affinity of chlorine. 
Enthalpy change	Value of the enthalpy
change / kJ mol–1	
Enthalpy of atomisation of magnesium
1st Ionisation energy of magnesium
2nd Ionisation energy of magnesium
Enthalpy of formation of magnesium chloride
Enthalpy of atomisation of chlorine
Lattice enthalpy of magnesium chloride	+150
+736
+1450
–642
+121
–2493	

(2)
 
(c)	Hydrogen gas reacts with sodium metal to form an ionic solid, NaH, which contains sodium cations.
	Draw a Born-Haber cycle which could be used to determine the electron affinity of hydrogen.

(3)
(Total 11 marks)

7.	(a)	Complete the following table:
Particle	Relative charge	Relative mass	
Proton		1	
Electron	–1		
Neutron		1	
(3)
 
(b)	State the number of each of the above particles present in one molecule of CH4, showing clearly how you arrive at your answer.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(3)
 
(c)	Complete the electronic configuration of a chlorine atom.
1s2 ............................................................................................................................
(1)
 
(d)	Give the formula of the chlorine species composed of 17 protons, 20 neutrons and 16 electrons.
....................................................................................................................................
(2)
 
(e)	Write one equation in each case to represent the change occurring when the following quantities are measured.
(i)	The first electron affinity of sulphur.
............................................................................................................................
(2)
 
(ii)	The first ionisation energy of sulphur.
........................................................................................................................
(1)
 
(f)	Explain why the first ionisation energy of chlorine is higher than that of sulphur.
....................................................................................................................................
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(2)
(Total 14 marks)

8.	(a)	(i)	Complete the electronic configuration of calcium.
1s2 ....................................................................................................................
(1)

(ii)	State the number of electrons in the outer shell of an atom of chlorine.
………………………………………………………………………………..
(1)
 
(b)	(i)	Write the equation for the reaction of calcium with chlorine to produce calcium chloride.
………………………………………………………………………………..
(1)
 
(ii)	Name the type of bonding in calcium chloride.
………………………………………………………………………………..
(1)
 
(iii)	Draw a dot and cross diagram for calcium chloride showing all the outer electrons.

(3)
(Total 7 marks)

9.	Both magnesium metal and molten magnesium chloride conduct electricity, but solid magnesium chloride does not.
(a)	Describe the structure of magnesium metal and explain why the solid conducts electricity.
………….…………………………………………………………………………….
………….…………………………………………………………………………….
………….…………………………………………………………………………….
………….…………………………………………………………………………….
(3)

(b)	Describe, in terms of the position and motion of the particles, what happens when some solid magnesium chloride, MgCl2, is heated from room temperature to just above its melting temperature.
………….…………………………………………………………………………….
………….…………………………………………………………………………….
………….…………………………………………………………………………….
………….…………………………………………………………………………….
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(4)
 
(c)	Explain why magnesium chloride can conduct electricity when molten, but not when solid.
………….…………………………………………………………………………….
………….…………………………………………………………………………….
………….…………………………………………………………………………….
………….…………………………………………………………………………….
(2)
(Total 9 marks)

10.	Nitrogen and phosphorus are in the same group of the Periodic Table. Phosphorus and hydrogen form the compound phosphine, PH3, and nitrogen and hydrogen form ammonia, NH3.
(a)	(i)	State the number of bond pairs and lone pairs of electrons in a molecule of phosphine.
Bond pairs of electrons: .....................   Lone pairs of electrons: ....................
(2)

(ii)	Use your answer to (i) to draw the shape of the molecule and indicate on your diagram the approximate HPH bond angle that you would expect.

(2)
 
(b)	The boiling temperature of ammonia is –33 °C and that of phosphine –88°C.
(i)	List all the intermolecular forces that exist between molecules of ammonia.
………….……………….……………………………………………………..
………….……………….……………………………………………………..
………….……………….……………………………………………………..
………….……………….……………………………………………………..
(2)
 
(ii)	Explain why the boiling temperature of phosphine is lower than that for ammonia.
………….……………….……………………………………………………..
………….……………….……………………………………………………..
………….……………….……………………………………………………..
………….……………….……………………………………………………..
(2)
 
(c)	Ammonia forms a dative covalent bond with H+ ions to form the ammonium ion, NH4+.
(i)	Explain what is meant by the term dative covalent bond.
………….……………….……………………………………………………..
………….……………….……………………………………………………..
(2)

(ii)	What part of the ammonia molecule enables it to form such a bond?
………….……………….……………………………………………………..
(1)
 
(iii)	State and explain the shape of the ammonium ion, NH4+.
………….……………….……………………………………………………..
(3)
(Total 14 marks)

11.	In an experiment to show the migration of ions, silver(I) nitrate solution, AgNO3(aq), and potassium chromate(VI) solution, K2CrO4(aq), were used. The experiment was set up as shown in the diagram below. After a short while, a red precipitate formed in the centre of the filter paper.

(a)	Write the formulae, including charges, of the following ions:
(i)	Nitrate ions .......................................................................................................
(ii)	Chromate (VI) ions ..........................................................................................
(2)
 
(b)	Which ions would meet in the centre of the filter paper?
....................................................................................................................................
(1)

(c)	Write a balanced ionic equation, including state symbols, for the formation of the red precipitate.

(2)
(Total 5 marks)

12.	(a)	Draw a ‘dot-and-cross’ diagram for a magnesium ion.
	Show ALL the electrons present and give the charge on this ion.

(2)
 
(b)	Why do salts containing magnesium ions give no colour in a flame test?
....................................................................................................................................
....................................................................................................................................
(1)
(Total 3 marks)

13.	The element gallium has two isotopes.
	
(a)	(i)	State ONE similarity and ONE difference between these two isotopes in terms of the numbers of their fundamental particles.
Similarity ..........................................................................................................
Difference .........................................................................................................
(2)
 
(ii)	The molar mass of a sample of gallium is 69.8 g mol–1.
	Calculate the percentage abundance of the isotope in the sample.

(2)
 
(b)	The first four ionisation energies of gallium are plotted below.

(i)	Write the chemical equation, with state symbols, which corresponds to the first ionisation energy of gallium.

(2)
 
(ii)	Why is there a general rise in the ionisation energy as successive electrons are removed?
..........................................................................................................................
..........................................................................................................................
(1)
 
(iii)	Explain why there is a comparatively large increase in value between the third and fourth ionisation energies.
..........................................................................................................................
..........................................................................................................................
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..........................................................................................................................
(2)
 
(c)	(i)	Suggest the formula of gallium chloride.
(You may find it helpful to refer to the Periodic Table.)
..........................................................................................................................
(1)

(ii)	Gallium chloride dissolves in water to form a solution containing ions.
	Suggest an experiment to show that the solution contains ions. State the result you would expect.
Experiment .......................................................................................................
..........................................................................................................................
..........................................................................................................................
Result ...............................................................................................................
(2)
(Total 12 marks)

14.	Phosphorus(III) chloride, PCl3, can be formed by the reaction of phosphorus and chlorine.
2P(s)  + 3Cl2(g)  ®  2PCl3(s)
(a)	(i)	Calculate the maximum mass of phosphorus(III) chloride, PCl3, which could be obtained from 93.0 g of phosphorus.

(3)

(ii)	Calculate the minimum volume of chlorine required to react completely with 93.0 g of phosphorus.
[One mole of gas occupies a volume of 24.0 dm3 under the conditions of the experiment].

(2)
 
(iii)	Identify the oxidising agent in the above reaction and explain your answer.
.....................................................................................................................................
.....................................................................................................................................
(2)
 
(b)	(i)	Draw a dot and cross diagram for a molecule of PCl3.

(2)

(ii)	Draw the predicted shape of a PCl3 molecule and mark on the diagram a value for the bond angle.

(2)
 
(c)	Suggest the name for the shape of the PCl4+ ion.
...............................................................................................................................................
(1)
(Total 12 marks)

15.	(a)	State the type of bonding in the following substances and draw diagrams to illustrate their 3-dimensional structures.
	Diamond
	Bonding ..............................................................
	Diagram

(3)
 
(b)	Explain why sodium chloride conducts electricity when molten but not when solid.
.....................................................................................................................................
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(2)
(Total 5 marks)

16.	(a)	(i)	Define the term first ionisation energy.
................................................................................................................................
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................................................................................................................................
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(3)
 
(ii)	State and explain the general trend in the first ionisation energy across the period sodium to argon of the Periodic Table.
................................................................................................................................
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................................................................................................................................
................................................................................................................................
................................................................................................................................
(3)
 
(b)	(i)	Write an equation to illustrate the process occurring when the second electron affinity of nitrogen is measured.
...............................................................................................................................
(2)
 
(ii)	Explain why the second electron affinity of any element is endothermic.
.....................................................................................................................................
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(2)
(Total 10 marks)

17.	Sodium is a reactive, silver-grey element from Group 1 of the Periodic Table.
(a)	(i)	What name is given to the type of bonding in this element? Draw a diagram to illustrate this type of bonding.
Name .................................................................................................................

(2)
 
(ii)	Sodium reacts readily with other elements such as chlorine.
		2Na(s)	+	Cl2(g)		2NaCl(s)
	sodium		chlorine		sodium chloride
	Draw a ‘dot-and-cross’ diagram, showing outer electrons only, of the ionic compound sodium chloride. Indicate charges clearly on your diagram.

(2)

(iii)	Would you expect the radius of a sodium ion to be larger than, smaller than or the same as the radius of a sodium atom? Give TWO reasons to justify your answer.
............................................................................................................................
............................................................................................................................
............................................................................................................................
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(3)
 
(b)	The table shows the first four ionisation energies for another element.
Ionisation Energy / kJ mol–1	
1st	2nd	3rd	4th	
738	1451	7733	10 541	
	To which Group of the Periodic Table does the element belong? Use the data to give a reason for your answer.
Group ..........................................................................................................................
Reason .........................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)

(c)	The graph below shows the first ionisation energies of the elements in Period 3. One noticeable feature of this graph is the dip from magnesium to aluminium. Use your knowledge of quantum levels and sub-levels to suggest an explanation for this dip.

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.................................................................................................................................
(2)

(d)	The Periodic Table shown here is from a website designed to help students understand the idea of periodicity. The heights of the shaded bars represent the melting points of the elements.

Source: www.schoolscience.co.uk/ptgraphs.html
 
(i)	Another table on this website shows the boiling points of the elements. 
Suggest ONE similarity and ONE difference between the two tables.
Similarity
............................................................................................................................
............................................................................................................................
Difference
............................................................................................................................
............................................................................................................................
(2)
 
(ii)	Name ONE other physical property, not mentioned in this question, that exhibits periodicity.
............................................................................................................................
(1)
(Total 14 marks)

18.	Phosphine, PH3, is a hydride of the Group 5 element, phosphorus.
(a)	(i)	Draw a ‘dot-and-cross’ diagram of a phosphine molecule. You should include only outer shell electrons.

(1)
 
(ii)	Draw the shape you would expect for the phosphine molecule, suggesting a value for the HPH bond angle.

HPH bond angle .......................................................................................................
(2)
 
(iii)	Explain the shape of the phosphine molecule you have given in your answer in (ii).
	Justify your value for the HPH bond angle.
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
.............................................................................................................................
(2)
 
(b)	(i)	Write a balanced equation, including state symbols, for the atomisation of phosphine gas.
.............................................................................................................................
(1)

(ii)	Use your answer to (i) and the data below to calculate the standard enthalpy change of atomisation of phosphine at 298 K. Include a sign and units in your answer.
ΔHοf[PH3(g)]	=	+	5.4 kJ mol-1
ΔHοat[½H2(g)]	=	+	218.0 kJ mol-1
ΔHοat[P(s)]	=	+	314.6 kJ mol-1

(3)
 
(iii)	Calculate a value for the bond energy of the bond between phosphorus and hydrogen, using your answer to (ii).

(1)
(Total 10 marks)

19.	(a)	When an oxygen atom, O, is changed into an oxide ion, O2–, is this oxidation or reduction? Justify your answer.
......................................................................................................................................
......................................................................................................................................
(1)

(b)	Draw a ‘dot-and-cross’ diagram for the oxide ion, O2–, showing all of the electrons.

(1)
 
(c)	Give the formulae of a positively charged ion, a neutral atom and a negatively charged ion with the same number and arrangement of electrons as the oxide ion.
	Formula	
Positively charged ion		
Neutral atom		
Negatively charged ion		
(Total 3 marks)

20.	Give TWO errors in this representation of the simple model of metallic bonding in sodium.

Error 1 .................................................................................................................................
Error 2 .................................................................................................................................
(Total 2 marks)

21.	This question is about ammonium dichromate(VI), (NH4)2Cr2O7(s), which is slightly soluble in water. Ammonium dichromate(VI) can be prepared by the following reaction:
Na2Cr2O7(aq) + 2NH4NO3(aq) ® (NH4)2Cr2O7(s) + 2NaNO3(aq)
(a)	What type of reaction is this?
......................................................................................................................................
(1)
 
(b)	(i)	Give the formulae of the ions present in ammonium dichromate(VI).
...............................................................................................................................
(2)
(ii)	Re-write the equation as an ionic equation, but omit any spectator ions.

(1)
 
(iii)	An orange crystal of ammonium dichromate(VI) was placed in the centre of a piece of moist filter paper supported on a glass microscope slide.

	Describe what you would expect to see when electricity is passed through the circuit.
...............................................................................................................................
(1)

(c)	(i)	Calculate the mass of 1 mole of ammonium dichromate(VI). Use the Periodic Table as a source of data.

(1)
 
(ii)	In an experiment to prepare ammonium dichromate(VI), 0.1 mol of sodium dichromate(VI) was used.
	What is the maximum mass of ammonium dichromate(VI) which could be obtained?

(1)
 
(iii)	What volume of ammonium nitrate solution of concentration 2 mol dm–3 would react exactly with 0.1 mol of sodium dichromate(VI)?

(1)
 
(iv)	Describe how you would obtain pure, dry crystals of ammonium dichromate(VI) from the resultant mixture.
...............................................................................................................................
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...............................................................................................................................
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(3)

(v)	Suggest TWO reasons why the mass of ammonium dichromate(VI), prepared in this way, is likely to be less than the mass calculated in (ii).
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
(2)
(Total 13 marks)

22.	Magnesium burns in oxygen to form magnesium oxide, MgO.
(a)	Write the equation for the reaction.
......................................................................................................................................
(1)
 
(b)	Draw a dot and cross diagram of magnesium oxide. Show all the electrons.

(2)

(c)	Describe the bonding in magnesium. Explain why it is a good conductor of electricity.
......................................................................................................................................
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......................................................................................................................................
(3)
(Total 6 marks)

23.	The values of the lattice energies of potassium iodide and calcium iodide experimentally determined from Born-Haber cycles and theoretically calculated from an ionic model are shown below.
	Experimental lattice
energy
/kJ mol–1	Theoretical
lattice energy
/kJ mol–1	
Potassium iodide, KI(s)	– 651	– 636	
Calcium iodide, CaI2(s)	–2074	–1905	

(i)	Explain why the experimental lattice energy of potassium iodide is less exothermic than the experimental lattice energy of calcium iodide.
.....................................................................................................................................
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.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
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(3)
 
(ii)	Explain why the experimental and theoretical values of the lattice energy are almost the same for potassium iodide, but are significantly different for calcium iodide.
.....................................................................................................................................
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(3)
(Total 6 marks)

24.	(a)	(i)	Write a balanced equation which represents the change that corresponds to the second ionisation energy of magnesium. Include state symbols in your answer.

(2)
 
(ii)	The graph below shows how the second ionisation energy of six consecutive elements in the Periodic Table, represented by the letters A to F, varies with increasing atomic number.

	Which of the elements, A to F, could represent magnesium?
..........................................
(1)
 
(b)	Draw a ‘dot and cross’ diagram to show the ions in magnesium fluoride.
Include all electrons and the charges on the ions.

(2)
(Total 5 marks)

25.	(a)	One of the naturally occurring potassium isotopes is 39K.
(i)	Write down the numbers of protons, neutrons and electrons present in an atom of 39K. Use the Periodic Table as a source of data.
	protons ......................	electrons ....................
	neutrons ....................
(2)
 
(ii)	Write down the electronic configuration of a potassium atom using s,p,d notation.
...............................................................................................................................
(1)
 
(b)	To show that potassium manganate(VII), KMnO4, is ionic, the apparatus below can
be used.

	The power supply is connected for about 30 minutes.
 
(i)	Give the formula of the coloured ion present in potassium manganate(VII),
KMnO4.
...............................................................................................................................
(1)

(ii)	What would you expect to see after 30 minutes?
................................................................................................................................
................................................................................................................................
................................................................................................................................
................................................................................................................................
(1)
 
(iii)	The gel was replaced with one containing copper(II) sulphate and the experiment repeated. Describe and explain what would be seen.
................................................................................................................................
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................................................................................................................................
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(2)
(Total 7 marks)
	Diagram adapted from Nuffield Advanced Science Chemistry Student’s Book, 4th Edition, p. 64, Fig. 3.20.

26.	(a)	Draw the ammonia molecule, NH3, making its three-dimensional shape clear. Mark in the bond angle on your diagram. Explain why ammonia has this shape and this bond angle.
	Diagram

	Explanation
.....................................................................................................................................
.....................................................................................................................................
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(4)
 
(b)	Explain whether ammonia is a polar molecule or not.
.....................................................................................................................................
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.....................................................................................................................................
(2)

(c)	Explain, in terms of the intermolecular forces in both compounds, why ammonia has a higher boiling temperature than phosphine, PH3.
.....................................................................................................................................
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.....................................................................................................................................
.....................................................................................................................................
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.....................................................................................................................................
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(3)
 
(d)	(i)	Explain, in terms of electrons, how ammonia can react with hydrogen ions to form ammonium ions, NH4+.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
 
(ii)	State the number of protons and the number of electrons present in an ammonium ion.
	number of protons .....................................
	number of electrons....................................
(2)
(Total 13 marks)

27.	(a)	Sodium chloride, NaCl, can be made by the reaction of sodium with chlorine.
2Na(s) + Cl2(g) ® 2NaCl(s)
(i)	Calculate the maximum mass of sodium chloride which could be obtained from 92 g of sodium.

(2)
 
(ii)	Calculate the concentration of the solution obtained when this mass of sodium chloride is dissolved in water and made up to a volume of 10 dm3 with distilled water.

(1)
 
(iii)	Calculate the volume of chlorine gas required to react with 92 g of sodium.
	[1 mol of gas occupies 24 dm3 under the conditions of the experiment]

(2)

(b)	Describe the structure of solid sodium metal and explain why it conducts electricity.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(3)
 
(c)	(i)	Define the term first ionisation energy.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
 
(ii)	Explain why the first ionisation energy of chlorine is higher than that of sodium.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(Total 13 marks)

28.	(a)	Define the term oxidising agent in terms of electron transfer.
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(1)

(b)	(i)	Suggest which halogen is the strongest oxidising agent.
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(1)
 
(ii)	What is the physical state of bromine at room temperature?
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(1)
 
(c)	State the appearance of a gas evolved when concentrated sulphuric acid is added to solid sodium bromide.
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(1)
 
(d)	Give the oxidation number of chlorine in each of the following species.
ClO– ......................................................................
ClO3– ......................................................................
(2)
 
(e)	Chlorine reacts with sodium hydroxide.
	Write an ionic equation for this reaction and explain, in terms of oxidation numbers, why this is a disproportionation reaction.
	Equation
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	Explanation
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(4)

(f)	(i)	Write an equation, including state symbols, to show the process that occurs when the first electron affinity of chlorine is measured.
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(2)
 
(ii)	Explain why the second electron affinity of chlorine would be endothermic.
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(2)
(Total 14 marks)

29.	(a)	Calculate the number of atoms in 3.50 g of lithium.
	Use the Periodic Table as a source of data.
	[The Avogadro constant, L = 6.02 × 1023 mol–1]

(2)

(b)	The equation for the reaction of lithium with hydrochloric acid is shown below.
2Li(s) + 2HCl(aq) ® 2LiCl(aq) + H2(g)
(i)	Rewrite this equation as an ionic equation, omitting the spectator ions.

(1)
 
(ii)	Draw a ‘dot and cross’ diagram of lithium chloride showing all the electrons. Indicate charges clearly on your diagram.

(2)

(iii)	The value of the standard enthalpy change for the reaction, DHο, is –557 kJ mol–1. State TWO of the reaction conditions necessary for this enthalpy change to be standard.
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(2)
(Total 7 marks)

30.	(a)	Methane and poly(ethene) are both hydrocarbons.
(i)	State the type of bond between carbon and hydrogen atoms in the molecules of both compounds.
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(1)
 
(ii)	State the type of intermolecular force present in both compounds.
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(1)
 
(iii)	Explain why poly(ethene) melts at a higher temperature than methane.
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(3)

(b)	Explain, in terms of its bonding, why magnesium has a high melting temperature.
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(2)
(Total 7 marks)

31.	(a)	The electrical conductivities of the elements in the Periodic Table show periodicity.
	What is meant by periodicity?
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(2)
 
(b)	Describe the periodic pattern of electrical conductivity.
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(1)
 
(c)	State ONE other physical property of an element which shows a periodic pattern.
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(1)
(Total 4 marks)

32.	The Hess cycle below can be used to estimate the enthalpy change of formation, DHf, of the unstable gaseous compound with the formula HOCl(g).

(a)	(i)	Insert formulae, with state symbols, into the appropriate boxes, to show the correct quantities of each element.
(1)
 
(ii)	Use the cycle to calculate a value for the enthalpy change of formation, [HOCl(g)].

(1)

(iii)	Assuming that the H—O bond energy is +464 kJ mol–1, calculate a value for the O—Cl bond energy.

(1)

(b)	(i)	Draw a ‘dot and cross’ diagram for the HOCl molecule showing outer electrons only.

(2)
(ii)	Predict the HOCl bond angle. Justify your answer.
Angle ................................................................................................................
Justification ......................................................................................................
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(2)

(c)	HOCl(g) can be made from chlorine(I) oxide by the reversible reaction
Cl2O(g) + H2O(g)  2HOCl(g)
	What effect, if any, would an increase in pressure have on the proportion of HOCl(g) at equilibrium? Justify your answer.
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(2)
(Total 9 marks)

33.	(a)	Complete the table below which is about isotopes and an ion of magnesium.
	Numbers of	
	Protons	Neutrons	Electrons	
	12	12		
	12		12	
	12	12		
(3)
 
(b)	Complete the electronic configurations of magnesium and chlorine atoms.
		1s	2s	2p	3s	3p
Mg	↓↑		↓↑											
(1)
		1s	2s	2p	3s	3p
Cl	↓↑		↓↑											
(1)

(c)	Write the equation, including state symbols, for the reaction of magnesium with chlorine.
.....................................................................................................................................
(2)
 
(d)	The mass spectrum of a sample of chlorine molecules shows three molecular peaks.
These are formed from the molecules shown below.
Molecule	Percentage abundance	
35Cl-35Cl	56.25	
35Cl-37Cl	37.50	
37Cl-37Cl	6.25	
	Calculate the relative molecular mass of chlorine in this sample.

(2)
 
(e)	Calculate the volume of 4.73 g of chlorine gas at 100 °C.
	[The molar volume of a gas at 100 °C = 30.6 dm3 mol–1]

(2)

(f)	State and explain the type of bond that exists in solid magnesium.
Type ..............................................................
Explanation  ................................................................................................................
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(3)
 
(g)	State the type of bond that exists in magnesium chloride. Draw a dot and cross diagram showing the outer shell electrons.
Type ..............................................................
Dot and cross diagram

(3)
(Total 17 marks)

34.	(a)	(i)	A diagram of the structure of solid sodium chloride is shown below.
	Label the diagram to identify the particles present in solid sodium chloride.
	
(1)
 
(ii)	Explain why sodium chloride has a high melting temperature.
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(2)
 
(b)	A diagram of the structure of solid graphite is shown below.
	On the diagram name and label the types of bonding that exist in solid graphite.
	
(2)

(c)	A diagram of the structure of solid diamond is shown below.
	On the diagram name and label the type of bond that exists in solid diamond.
	
(1)
 
(d)	The densities of diamond and graphite are
	Density / g cm–3	
Diamond	3.53	
Graphite	2.25	
	Suggest, using information from (b) and (c), why diamond is more dense than graphite.
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(2)
(Total 8 marks)

35.	(a)	What is the formula for strontium fluoride?
Use the Periodic Table as a source of information.
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(1)
 
(b)	Draw a ‘dot and cross’ diagram for the fluoride ion.
Include all electrons and the charge on the ion.

(1)
(Total 2 marks)

36.	State the type of bond that exists in sodium bromide.
	Draw a dot and cross diagram of sodium bromide, showing only the outer shell electrons.
Type .......................................................................................................................................
	Dot and cross diagram

(Total 3 marks)

(1)
(Total 2 marks)

37.	(a)	An incomplete Born-Haber cycle for the formation of magnesium oxide, MgO, from its constituent elements is shown below. All numerical values are in kJ mol–1.

(i)	Complete the empty box on the cycle by writing in the formulae of the missing species. State symbols are required.
(1)
 
(ii)	Identify each of the following enthalpy changes by name:
ΔH1 ....................................................................................................................
ΔH2 ....................................................................................................................
ΔH3 ....................................................................................................................
(3)
 
(iii)	Use the Born-Haber cycle to calculate the lattice energy of magnesium oxide.

(2)
 
(b)	Magnesium iodide is another compound of magnesium. The radius of the magnesium ion is 0.072 nm, whereas the radius of the iodide ion is much larger and is 0.215 nm.
(i)	Describe the effect that the magnesium ion has on an iodide ion next to it in the magnesium iodide lattice.
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(1)

(ii)	What TWO quantities must be known about the ions in a compound in order to calculate a theoretical lattice energy?
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(2)
 
(iii)	Suggest how the value of the theoretical lattice energy would compare with the experimental value from a Born-Haber Cycle for magnesium iodide.
	Give a reason for your answer.
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(2)
(Total 11 marks)

38.	Draw a ‘dot and cross’ diagram to show the ions in calcium oxide. Include ALL the electrons and charges.

(Total 2 marks)

39.	(a)	Fill in the table below to show the number of protons and electrons present in a hydride ion, H–, and a lithium ion, Li+.
	Use the Periodic Table as a source of data.
	Protons	Electrons	
H–			
Li+			
(2)
 
(b)	Which of these ions is larger, H– or Li+?
	Use the numbers you have entered in the table above to explain your answer.
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(2)
(Total 4 marks)

40.	(a)	Complete the electronic configuration of a copper atom and a bromide ion.
(i)	Copper atom, Cu	1s22s22p63s23p6 ..............................................................
(1)
(ii)	Bromide ion, Br–	1s22s22p63s23p6 ..............................................................
(1)

(b)	Define the term relative atomic mass.
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(2)
 
(c)	The following data were obtained for a mass spectrum of a sample of copper.
Relative isotopic mass	Percentage abundance	
62.93	69.17	
64.93	30.83	
	Calculate the relative atomic mass of this sample of copper. Give your answer to two decimal places.

(2)

(d)	Copper occurs naturally as the mineral malachite. The composition, by mass, of malachite is as follows:
	Cu = 57.5% C = 5.4% O = 36.2% H = 0.9%
(i)	Calculate its empirical formula.

(2)
 
(ii)	The molar mass of malachite is 221 g mol–1. Calculate its formula.

(1)
 
(e)	Copper forms a chloride, CuCl2. Use the data below to calculate the maximum and the minimum values for the molar mass of CuCl2.
Data :	Relative isotopic masses of chlorine are 35 and 37.
Relative isotopic masses of copper are 63 and 65.

(2)
(Total 11 marks)

41.	The Born-Haber cycle below represents the enthalpy changes when calcium hydride, CaH2, is formed from its elements.

(a)	Write down in terms of one of the symbols ΔH1 to ΔH6
(i)	the lattice energy of calcium hydride ................................................................
(1)
(ii)	the first electron affinity of hydrogen ................................................................
(1)

(b)	Use the data below to calculate the standard enthalpy of formation of calcium hydride, CaH2(s).
	value
/kJ mol–1	
enthalpy of atomisation of calcium	+178	
first plus second ionisation energies of calcium	+1735	
enthalpy of atomisation of hydrogen	+218	
first electron affinity of hydrogen	–73	
lattice energy of calcium hydride	–2389	
	Calculation:

(2)
 
(c)	Explain why the lattice energy of magnesium hydride, MgH2(s), is more exothermic than the lattice energy of calcium hydride, CaH2(s).
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(3)
(Total 7 marks)

42.	(a)	The following data were collected to use in a Born-Haber cycle for silver fluoride, AgF.
	Value
/kJ mol–1	
enthalpy of atomisation of silver	+285	
first ionisation energy of silver	+731	
enthalpy of atomisation of fluorine	+79	
enthalpy of formation of silver fluoride	–205	
lattice energy of silver fluoride	–958	
 
	On the following outline of a Born-Haber cycle, complete boxes A and B by adding the formula and state symbol for the appropriate species. Write the name of the enthalpy change at C.

(3)

(b)	ΔHlatt (theoretical) is the lattice energy calculated assuming the crystal lattice is completely ionic.
ΔHlatt (experimental) is the lattice energy determined experimentally using the Born-Haber cycle.
	Values for the silver halides are listed below.
Formula of halide	ΔHlatt
(theoretical)

/ kJ mol–1	ΔHlatt
(experimental)

/ kJ mol–1	ΔHlatt (theoretical)
minus
ΔHlatt (experimental)
/ kJ mol–1	
AgF	–920	–958	38	
AgCl	–833	–905	72	
AgBr	–816	–891	75	
AgI	–778	–889	111	
 
(i)	Explain why the theoretical lattice energies become less exothermic from AgF to AgI.
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(3)
 
(ii)	Explain why the values of the theoretical and experimental lattice energies are different.
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(2)

(iii)	Explain why the difference between the theoretical and experimental lattice energies increases from AgF to AgI.
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(2)
(Total 10 marks)

43.	(a)	The diagram shows the type of bonding present in the elements lithium and sodium in the solid state.

(i)	What name is given to this type of bonding?
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(1)
 
(ii)	Suggest why the melting point of lithium is greater than that of sodium.
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(2)

(b)	Lithium can react with chlorine to produce lithium chloride. When a sample of lithium chloride is heated in a Bunsen flame, a red colour is seen.
(i)	Draw a ‘dot and cross’ diagram of lithium chloride showing all the electrons.
Indicate the charges clearly on your diagram.

(2)
 
(ii)	Describe the changes that occur within the lithium ion to produce the flame colour.
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(2)
 
(iii)	Name ONE other metallic element whose compounds produce a red coloured flame.
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(1)
(Total 8 marks)

44.	Going across a period in the Periodic Table from left to right, the general trend is that
A	the bonding in the element itself changes from ionic to covalent
B	the number of neutrons in the nucleus increases
C	the first ionisation energy decreases
D	the metallic character increases
(Total 1 mark)

45.	This question is about magnesium and magnesium oxide.
(a)	Describe the bonding in magnesium and explain why it is a good conductor of electricity.
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(3)
 
(b)	Draw a diagram (using dots or crosses) for the ions in magnesium fluoride showing all the electrons and the ionic charges on:
(i)	the magnesium ion

(1)
(ii)	the fluoride ion.

(1)

(c)	Under what conditions does magnesium fluoride conduct electricity?
	Explain your answer.
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(1)
 
(d)	The mass spectrum of a sample of magnesium is shown below.

(i)	Use the data above to estimate the percentage isotopic composition of the sample of magnesium. Hence calculate the average atomic mass of the sample of magnesium.

(2)
 
(ii)	Why do the three isotopes have the same chemical properties?
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(1)
 
(e)	(i)	Oceanographers studying plankton found that a sample of seawater contained 1.20 nanomol dm–3 of chlorophyll, C55H77MgN4O5. (1 nanomol = 1 × 10–9 mol)
	What mass of magnesium would be present in 1.00 cm3 of this sample of seawater? Give your answer to three significant figures.

(2)
(ii)	X-ray diffraction can be used to locate atoms or ions in molecules like chlorophyll.
X-rays are scattered by the electrons in atoms and ions. In chlorophyll the atoms of one of the elements still cannot be located with certainty by this technique.
	Suggest which element is most difficult to locate.
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(1)
(Total 12 marks)