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General Certificate of EducationJanuary 2003Advanced Subsidiary Examination

CHEMISTRY CHM1Unit 1 Atomic Structure, Bonding and Periodicity

Friday 10 January 2003 Morning Session

For Examiner’s Use

Number

1

2

3

4

5

6

7

Mark Number Mark

Examiner’s Initials

TOTAL

Total(Column 2)

Total(Column 1)

APW/0103/CHM1

→

→

In addition to this paper you will require:a calculator.

Time allowed: 1 hour 30 minutes

Instructions• Use blue or black ink or ball-point pen.• Fill in the boxes at the top of this page.• Answer all questions in Section A and Section B in the spaces provided.

All working must be shown.• Do all rough work in this book. Cross through any work you do not

want marked.• The Periodic Table/Data Sheet is provided on pages 3 and 4. Detach this

perforated sheet at the start of the examination.

Information• The maximum mark for this paper is 90.• Mark allocations are shown in brackets.• This paper carries 30 per cent of the total marks for AS. For Advanced

Level this paper carries 15 per cent of the total marks.• You are expected to use a calculator where appropriate.• The following data may be required.

Gas constant R = 8.31 J K–1 mol–1

• Your answers to questions in Section B should be written in continuousprose, where appropriate. You will be assessed on your ability to use anappropriate form and style of writing, to organise relevant informationclearly and coherently, and to use specialist vocabulary, whereappropriate.

Advice• You are advised to spend about 1 hour on Section A and about

30 minutes on Section B.

CHM1 pgs 1-16 10/10/02 10:18 am Page 1

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SECTION A

Answer all questions in the spaces provided.

1 (a) Complete the following table.

(3 marks)

(b) An atom of element Z has two more protons and two more neutrons than an atom of3416S. Give the symbol, including mass number and atomic number, for this atom of Z.

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

(c) Complete the electronic configurations for the sulphur atom, S, and the sulphide ion, S2–.

S l s2 ..................................................................................................................................

S2– l s2 ..................................................................................................................................(2 marks)

(d) State the block in the Periodic Table in which sulphur is placed and explain your answer.

Block .............................................................................................................................................

Explanation ..................................................................................................................................(2 marks)

Particle Relative charge Relative mass

Proton

Neutron

Electron

CHM1 pgs 1-16 10/10/02 10:18 am Page 2

1.0

HH

ydro

gen

1

4.0H

eH

eliu

m2

10.8B

Bor

on5

12.0C

Car

bon

6

14.0N

Nitr

ogen

7

16.0O

Oxy

gen

8

19.0

FF

luor

ine

9

20.2 N

eN

eon

10

27.0 A

lA

lum

iniu

m13

28.1 S

iS

ilico

n14

31.0

PP

hosp

horu

s15

32.1

SS

ulph

ur16

35.5 C

lC

hlor

ine

17

39.9 A

rA

rgon

18

6.9

Li

Lith

ium

3

6.9

Li

Lith

ium

3

9.0B

eB

eryl

lium

4

III

IIIIV

VV

IV

II0

*58

– 7

1La

ntha

nide

s

†90

– 1

03A

ctin

ides

Key

rela

tive

atom

ic m

ass

atom

ic n

umbe

r

Th

e P

erio

dic

Tab

le o

f th

e E

lem

ents

�T

he a

tom

ic n

umbe

rs a

nd a

ppro

xim

ate

rela

tive

ato

mic

mas

ses

show

n in

the

tab

le a

re f

or u

se in

the

exa

min

atio

n un

less

sta

ted

othe

rwis

e in

an

indi

vidu

al q

uest

ion.

23.0 N

aS

odiu

m11 39

.1K

Pot

assi

um19

40.1 C

aC

alci

um20

45.0 S

cS

cand

ium

21

47.9 T

iT

itani

um22

50.9

VV

anad

ium

23

52.0 C

rC

hrom

ium

24

54.9 M

nM

anga

nese

25

55.8 F

eIr

on26

58.9 C

oC

obal

t27

58.7 N

iN

icke

l28

63.5 C

uC

oppe

r29

65.4 Z

nZ

inc

30

69.7 G

aG

alliu

m31

72.6 G

eG

erm

aniu

m32

74.9 A

sA

rsen

ic33

79.0 S

eS

elen

ium

34

79.9 B

rB

rom

ine

35

83.8 K

rK

rypt

on36

85.5 R

bR

ubid

ium

37

87.6 S

rS

tron

tium

38

88.9

YY

ttriu

m39

91.2 Z

rZ

ircon

ium

40

92.9 N

bN

iobi

um41

95.9 M

oM

olyb

denu

m42

98.9 T

cTe

chne

tium

43

101.

1 Ru

Rut

heni

um44

102.

9 Rh

Rho

dium

45

106.

4 Pd

Pal

ladi

um46

107.

9 Ag

Silv

er47

112.

4 Cd

Cad

miu

m48

114.

8 InIn

dium

49

118.

7 Sn

Tin

50

121.

8 Sb

Ant

imon

y51

127.

6 TeTe

lluriu

m52

126.

9 IIo

dine

53

131.

3 Xe

Xen

on54

132.

9 Cs

Cae

sium

55

137.

3 Ba

Bar

ium

56

138.

9 La

Lant

hanu

m57

*

178.

5 Hf

Haf

nium

72

180.

9 TaTa

ntal

um73

183.

9 WTu

ngst

en74

186.

2 Re

Rhe

nium

75

190.

2 Os

Osm

ium

76

192.

2 IrIr

idiu

m77

195.

1 Pt

Pla

tinum

78

197.

0 Au

Gol

d79

200.

6 Hg

Mer

cury

80

204.

4 Tl

Tha

llium

81

207.

2 Pb

Lead

82

209.

0 Bi

Bis

mut

h83

210.

0 Po

Pol

oniu

m84

210.

0 At

Ast

atin

e85

222.

0 Rn

Rad

on86

223.

0 Fr

Fran

cium

87

226.

0 Ra

Rad

ium

88

227 A

cA

ctin

ium

89

†

140.

1 Ce

Cer

ium

58

140.

9 Pr

Pras

eody

miu

m59

144.

2 Nd

Neo

dym

ium

60

144.

9 Pm

Pro

met

hium

61

150.

4 Sm

Sam

ariu

m62

152.

0 Eu

Eur

opiu

m63

157.

3 Gd

Gad

olin

ium

64

158.

9 Tb

Terb

ium

65

162.

5 Dy

Dys

pros

ium

66

164.

9 Ho

Hol

miu

m67

167.

3 Er

Erb

ium

68

168.

9 Tm

Thu

lium

69

173.

0 Yb

Ytte

rbiu

m70

175.

0 Lu

Lute

tium

71

232.

0 Th

Tho

rium

90

231.

0 Pa

Pro

tact

iniu

m91

238.

0 UU

rani

um92

237.

0 Np

Nep

tuni

um93

239.

1 Pu

Plu

toni

um94

243.

1 Am

Am

eric

ium

95

247.

1 Cm

Cur

ium

96

247.

1 Bk

Ber

keliu

m97

252.

1 Cf

Cal

iforn

ium

98

(252

) Es

Ein

stei

nium

99

(257

) Fm

Fer

miu

m10

0

(258

) Md

Men

dele

vium

101

(259

) No

Nob

eliu

m10

2

(260

) Lr

Law

renc

ium

103

24.3 M

gM

agne

sium

12

APW/0103/CHM1

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CHM1 pgs 1-16 10/10/02 10:18 am Page 3

Table 1Proton n.m.r chemical shift data

Type of proton δ/ppm

RCH3 0.7–1.2

R2CH2 1.2–1.4

R3CH 1.4–1.6

RCOCH3 2.1–2.6

ROCH3 3.1–3.9

RCOOCH3 3.7–4.1

ROH 0.5–5.0

Table 2Infra-red absorption data

Bond Wavenumber/cm–1

C—H 2850–3300

C—C 750–1100

C C 1620–1680

C O 1680–1750

C—O 1000–1300

O—H (alcohols) 3230–3550

O—H (acids) 2500–3000

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(e) Sodium sulphide, Na2S, is a high melting point solid which conducts electricity whenmolten. Carbon disulphide, CS2, is a liquid which does not conduct electricity.

(i) Deduce the type of bonding present in Na2S and that present in CS2

Bonding in Na2S ................................................................................................................

Bonding in CS2 ..................................................................................................................

(ii) By reference to all the atoms involved explain, in terms of electrons, how Na2S isformed from its atoms.

.............................................................................................................................................

.............................................................................................................................................

(iii) Draw a diagram, including all the outer electrons, to represent the bonding presentin CS2

(iv) When heated with steam, CS2 reacts to form hydrogen sulphide, H2S, and carbon dioxide.Write an equation for this reaction.

.............................................................................................................................................(7 marks)

TURN OVER FOR THE NEXT QUESTION

16

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2 (a) Calculate the concentration, in mol dm–3, of the solution formed when 19.6 g ofhydrogen chloride, HCl, are dissolved in water and the volume made up to 250 cm3.

.......................................................................................................................................................

.......................................................................................................................................................

.......................................................................................................................................................(3 marks)

(b) The carbonate of metal M has the formula M2CO3. The equation for the reaction of thiscarbonate with hydrochloric acid is given below.

M2CO3 + 2HCl → 2MCl + CO2 + H2O

A sample of M2CO3, of mass 0.394 g, required the addition of 21.7 cm3 of a 0.263 mol dm–3 solution of hydrochloric acid for complete reaction.

(i) Calculate the number of moles of hydrochloric acid used.

.............................................................................................................................................

.............................................................................................................................................

(ii) Calculate the number of moles of M2CO3 in 0.394 g.

.............................................................................................................................................

.............................................................................................................................................

(iii) Calculate the relative molecular mass of M2CO3

.............................................................................................................................................

.............................................................................................................................................

(iv) Deduce the relative atomic mass of M and hence suggest its identity.

Relative atomic mass of M ..............................................................................................

.............................................................................................................................................

Identity of M .....................................................................................................................(6 marks)

9

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3 When a sample of liquid, X, of mass 0.406 g was vaporised, the vapour was found to occupy avolume of 2.34 × 10–4 m3 at a pressure of 110 kPa and a temperature of 473 K.

(a) Give the name of the equation pV = nRT.

.......................................................................................................................................................(1 mark)

(b) Use the equation pV = nRT to calculate the number of moles of X in the sample andhence deduce the relative molecular mass of X.(The gas constant R = 8.31 J K–1 mol–1)

Moles of X ....................................................................................................................................

.......................................................................................................................................................

.......................................................................................................................................................

Relative molecular mass of X .....................................................................................................

.......................................................................................................................................................(4 marks)

(c) Compound X, which contains carbon, hydrogen and oxygen only, has 38.7% carbon and9.68% hydrogen by mass. Calculate the empirical formula of X.

.......................................................................................................................................................

.......................................................................................................................................................

.......................................................................................................................................................

.......................................................................................................................................................(3 marks)

(d) Using your answers to parts (b) and (c) above, deduce the molecular formula of X.

.......................................................................................................................................................

.......................................................................................................................................................(1 mark)

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4 (a) The boiling point of H2O is 373 K and that of H2S is 212 K.

(i) Name the strongest type of intermolecular attraction present in water.

.............................................................................................................................................

(ii) Name the strongest type of intermolecular attraction present in hydrogensulphide.

.............................................................................................................................................

(iii) Explain why the boiling point of water is so much higher than that of hydrogensulphide.

.............................................................................................................................................

.............................................................................................................................................(4 marks)

(b) Define the term electronegativity.

.......................................................................................................................................................

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

(c) State and explain the trend in electronegativity down Group II from Be to Ba.

Trend ............................................................................................................................................

Explanation .................................................................................................................................

.......................................................................................................................................................

.......................................................................................................................................................(3 marks)

(d) (i) Give the type of bonding present in BeCl2

.............................................................................................................................................

(ii) Give the type of bonding present in BaCl2

.............................................................................................................................................

(iii) Explain why the type of bonding is different in these two compounds.

.............................................................................................................................................

.............................................................................................................................................(3 marks)

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(e) (i) Explain what is meant by the term amphoteric. Write two equations involvingBe(OH)2 to illustrate your answer.

Explanation .......................................................................................................................

.............................................................................................................................................

Equation 1 .........................................................................................................................

Equation 2 .........................................................................................................................

(ii) In what way is this behaviour of Be(OH)2 atypical of the behaviour of Group IImetal hydroxides?

.............................................................................................................................................

.............................................................................................................................................(4 marks)

TURN OVER FOR THE NEXT QUESTION

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5 There is a general trend in the values of the first ionisation energies of the elements Na to Ar.The first ionisation energies of the elements Al and S deviate from this trend.

(a) Write an equation, including state symbols, to represent the process for which the energychange is the first ionisation energy of Na.

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

(b) State and explain the general trend in the values of the first ionisation energies of theelements Na to Ar.

Trend ............................................................................................................................................

Explanation .................................................................................................................................

.......................................................................................................................................................

.......................................................................................................................................................(3 marks)

(c) State how, and explain why, the values of the first ionisation energies of the elements Al and S deviate from the general trend.

How the values deviate from the trend .....................................................................................

Explanation for Al ......................................................................................................................

.......................................................................................................................................................

.......................................................................................................................................................

Explanation for S ........................................................................................................................

.......................................................................................................................................................

.......................................................................................................................................................(5 marks)

10

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6 (a) Ionisation is the first of the four main stages involved in obtaining the mass spectrum ofa sample of gaseous titanium atoms. Explain how ionisation is achieved. Name theremaining three stages and, in each case, state how each stage is achieved. Explain whyit would be difficult to distinguish between 48Ti2+ and 24Mg+ ions using a massspectrometer. (10 marks)

(b) State any differences and similarities in the atomic structure of the isotopes of anelement. State the difference, if any, in the chemistry of these isotopes. Explain youranswer. (4 marks)

(c) The table below gives the percentage abundance of each isotope in the mass spectrumof a sample of titanium.

Define the term relative atomic mass of an element. Use the above data to calculate thevalue of the relative atomic mass of titanium in this sample. Give your answer to twodecimal places. (4 marks)

7 (a) Predict the shapes of the SF6 molecule and the AlCl4– ion. Draw diagrams of these

species to show their three-dimensional shapes. Name the shapes and suggest values forthe bond angles. Explain your reasoning. (8 marks)

(b) Perfume is a mixture of fragrant compounds dissolved in a volatile solvent.

When applied to the skin the solvent evaporates, causing the skin to cool for a short time.After a while, the fragrance may be detected some distance away. Explain theseobservations. (4 marks)

END OF QUESTIONS

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SECTION B

Answer both questions below in the space provided on pages 12 to 16 of this booklet.

m/z 46 47 48 49 50

% abundance 8.02 7.31 73.81 5.54 5.32

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