Al khor International School1 1.B[1]

2.C[1]

3.(a)(i)

electrons (1)charge (1)square brackets not essentialMark independentlyIgnore (labelling of) nucleus unless incorrect2 (ii)1s22s22p63s23p6Allow electron number as sub scriptAllow orbitals as capital lettersAllow TE from (a) (i) if Ca atom or Ca+ ion1 (iii)SmallerBecause it has one less (sub) shell of electrons / orbital / energy level /less shielding (1)And the ratio of protons : electrons has increased / more protonsthan electrons / greater net force on remaining electrons (so remainderof electrons held more closely) / greater effective nuclear charge (1)2bigger scores zerogreater nuclear charge /positive charge

(iv)Any two from:Strong (electrostatic) forces / attractions / bonds (between ions) (1)(ions) held in giant lattice / many (ionic) attractions / forces / bonds (1)So large amount of energy needed (to break apart ions) (1)2Any mention of covalent or metallic bonds or atoms or molecules scores zeroHigh temperature (b)(i)Because the ions are free to move (when a potential difference is applied)1Electrons / particles are free to move (ii)The cations / barium and calcium (ions) are different sizesIgnore any discussion of reasons(could select either the calcium ion because it has more watermolecules associated with it OR the barium ion because it hasmore shells of electrons and so larger)1Atoms are different sizes (iii)Mass of calcium ions in 1 kg = 0.100 40 (= 4.0) (g) (1)If mass quoted must be correct to score first markHence 4.0 g per 1000 g of solutionSo ppm = (4.0/1000) 1000000= 4000 (ppm) (1)ORMass of calcium ions in 1 kg = 0.100 40.1(= 4.01) (g) (1)Hence 4.01 g per 1000 g of solutionSo ppm = (4.01/1000) 1000000= 4010 (ppm) (1)Correct answer alone = 2 marksAllow TE for second mark from incorrect mass2

(c)(Sulfur / nitrogen oxides) form when (fossil) fuels are burnt/ when petrol or diesel burn in vehicle engines / emissions fromvehicle (engines)/ volcanoes/ lightning (1)They (react with water to) form sulfuric / sulfurous acid /nitric acid/acid rain / gases are acidic (1)Which reacts with limestone (to form soluble compounds) / limestoneand acid take part in neutralisation / dissolves building / corrodes building (1)Allow correct equation for third mark but Ignore equations if mark alreadyawarded.Ignore comments regarding erosion3from factories alone (d)EitherYes, as the values match closely (so little deviation from ionic model)Orno, as the values are (slightly) different so a degree of covalency / notfully ionic1100% ioniccovalent[15]

4.C[1]

5.D[1]

6.(a)B1 (b)A1 (c)D1[3]

7.D[1]

8.A[1]

9.B[1]

10.A[1]

11.C[1]

12.C[1]

13.(a)elementstructurebondingsodiumGiantmetallicsiliconGiant (atomic)/macromolecular/giant molecularcovalentsulfursimple / smallmolecules

OR

(simple)molecular

ORS8 moleculescovalent or vander Waalsforces/ Londonforces/intermolecularforces/dispersionforces/induced-dipoleforcesIGNORE the word lattice OR crystalline6 boxes correct (3)5,4 boxes correct (2)3,2 boxes correct (1)1,0 boxes correct (0)3 (b)Si : covalent bonds / many bonds/strong bonds (between atoms) (1)S : weak forces /van der Waalsforces/London forces/dispersionforces/intermolecularforces/induced-dipole forces (1)(need to be overcome)2any reference to intermolecular forces in Sisuggestion that covalent bonds are broken

(c)QWCCations/ions decrease in size (from Na+ to Al3+)ORcharge increases/charge density on (cat)ions increases/ effectivenuclear charge increases (from Na+ to Al3+) (1)more e (per atom in sea of delocalized electrons) / more delocalizedelectronsOR(force of) attraction between (cat)ions/nucleus and (delocalised) electronsincreases (from Na to Al) (1)IGNORE nuclear charge increases/ increasing no. of protons2atoms decrease in sizeany mention of molecules/covalent bonds/van der Waals forces/ionic bonds (0) overall (d)(i)Add MgO to acid/react MgO with acid/dissolve MgO in acid (1)[NOTE: mention of heating not required. IGNORE water bath/reflux]Filter (1)Heat/boil filtrate /MgSO4 solution (until volume reducedby half) (1)Leave to cool/leave to crystallise/evaporate slowly/leaveto evaporate (1)(decant / filter / pick out crystals, then)Leave to dry/pat dry/dry between filter papers/put in anoven/put in a desiccator/dry the crystals (1)5IGNORE any washing of crystals immediately prior to drying themJust warm the filtrate/MgSO4 solutionUse of a desiccant (added to crystals) (ii)Rinse with (plenty of) water /use a damp cloth or damp (paper) towel /add a (named) weak alkali (e.g. solid or aqueous sodiumhydrogencarbonate)1Any named strong alkali/just strong alkali (e)(i)Insoluble strontiumsulfate/insoluble SrSO4(forms on the strontium carbonate)1

(ii)Sr2+(aq) + SO42 (aq) SrSO4(s) species (1)state symbols (1)2nd mark is cq on first markSr2+(aq) + 2Cl(aq) + 2Na+(aq) + SO42(aq) SrSO4(s)+ 2Cl(aq) + 2Na+(aq)scores (1)SrCl2(aq) + Na2SO4(aq) SrSO4(s) + 2NaCl(aq)scores (1)2[16]

14.C[1]

15.C[1]

16.(a)(i)(1s2)2s22p63s2ALLOW subscriptsIGNORE capital lettersALLOW 2p as px py pz with two e- in each1Noble gas core (ii)(1s2)2s22p63s23p5ALLOW subscriptsIGNORE capital lettersALLOW 2p as px py pz with two e- in eachALLOW 3p as px py pz with two, two, one eineach1Noble gas core (b)(i)Mg(s) + Cl2(g) MgCl2(s)Species and balancing (1)State symbols CQ on correct species (1)NOTEMg(s) + 2Cl(g) MgCl2(s) scores (1)2

(ii)Ionic / electrovalentIGNORE lattice/bonding/giant1 (iii)Correct number of electrons on each ion (1)Correct charges and symbols for each ion (1)Correct ratio of ions (1)

ALLOW all dots or all crossesALLOW correct charges shown outside the ionsALLOW Cl correctly with 2 in front or after the Cl3Any covalency shown (0)i.e. any overlap of circles (e.g. Mg with a Cl or a Cl with a Cl)scores (0) overall, even if correct charges on ions and/orratio of ions has been shown (c)(Giant) metallic / metal1

(d)QWCMagnesium ion / Mg2+ has a larger charge (density) (than the sodium ion / Na+)ORMagnesium/Mg/Mg atom/Mg2+ (ion) contributes two electrons/more electrons(to the sea of electrons) (1)magnesium ions / Mg2+ smaller (than sodium ions) (1)NOTEMg2+ is smaller than Na+ would score first 2 marks abovemagnesium ions / Mg2+ have greater attraction for (sea of) electrons(than sodium ions / Na+)ORMore energy/heat required to overcome (attractive) forces/bonds(between cations and sea of electrons) in magnesium (comparedto sodium) (1)Mark each point independently3Any references to the bonding being ionic scores (0) overallAny references to molecules/intermolecular forces scores(0) overallJUST stronger bonds in MgJUST stronger bonds in Mg[12]

17.(a)(i)Idea of impact by electrons, with energy:electron gun alonefast electrons strike sample / high energy electrons /accelerated electrons / electrons fired at sample/samplebombarded with electrons/blasted with electronsfrom electron gun (1)Idea of electron removal:removes an electron/knocks out electron(s)/X X+ + e (1)Mark each point independently2an incorrect equation negates second mark (ii)Electric field/electrostatic field / charged plates / voltagedifferential across plates/negative field/negatively charged plates1Electric current/electric coil/magnetic field

(iii)Magnetic field / magnet / electromagnet / magnetic plates1Negative magnetic field (b)((50.0 4.3) + (52.0 83.8) + (53.0 9.5) + (54.0 2.4)) 100 (1)= 52.1 (must be to 3 SF) (1)NOTE: 52.057/52.06 scores (1) with or without any workingIGNORE g or g mol1 but wrong units lose a markCorrect answer with no working (2)2 (c)Same electronic structures/same electronic configurations/same electronicarrangements/same number of electrons/same total number of electronsALLOW same number of protons and same number of electrons1Just same number of outer electrons (0)ORJust same number of protons (0) (d)d (block)ALLOW D (BLOCK)IGNORE transition metal/element if d (block) stated in answerIGNORE group1Just transition element(s) / transition metal(s)[8]

18.B[1]

19.C[1]

20.B[1]

21.D[1]

22.B[1]

23.(a)A1 (b)B1 (c)D1[3]

24.(a)CuCO3(s) + H2SO4(aq) CO2(g) + CuSO4(aq) + H2O(l)1 (b)B1 (c)(i)(0.025 123.5) 1.1 = (1)3.396/ 3.40 / 3.4g (g) (1)OR0.025 mol copper carbonate = 3.087/3.09 (g)(1)3.087 +10% = 3.396/ 3.40/ 3.4 (g)Full marks for correct answer with no working2 (ii)No, as copper carbonate is in excess1Reject no, as molar mass is only to one decimal place (d)Filter to remove excess copper carbonate1 (e)(i)249.61

(ii)Expected yield = 0.025 249.6 (1)= 6.24g% yield = (100 3.98/6.24 )= 63.8/63.78% (1)2[9]

25.(a)QWC (i) & (iii)(Lattice of) positively charged ions/ ions with 2+charge (1)held together by (electrostatic) attraction to delocalised electrons (1)Delocalised electrons /free electrons/ electrons in sea of electronsare free to move and carry charge / current (1)3Reject incorrect use of the terms atom or molecule for ion.Reject incorrect descriptions of delocalised electrons. (b)(i)Mg2+ shown as 2,8 (1)1 (ii)F shown as 2,8 (1)1 (c)When molten/ when dissolved in water so that ions can move/lattice breaks down (1)1Reject dissolved in other solvents.Reject reference to atoms or molecules rather than ions. (d)(i)77% 24Mg, 10% 25Mg, 13% 26Mg (1)Average atomic mass = 24.36 = 24.4 g (1)2 (ii)Have same electron configuration1Reject same number of electrons in outer orbit (e)(i)1.20 109 mol of Mg per dm3 (1)(1.20 109 24.3 103) =2.92 1011 / 29.2 1012 (g) (1)max 1 for more/less than 3 significant figures eg 2.9162

(ii)Hydrogen because it has the least number of electrons per atom1[12]

26.(a)Energy/Enthalpy/heat change per mole for the (1)Accept required instead of changeRemoval of one electron (per atom) (1)From 1 mole of gaseous atoms (1)If wrong equation given with a correct definition (max 2)3X(g) X+(g) + e() can score last 2 marks (b)Increase in shielding/screening (1)Increase in nuclear charge/more protons/atomic number (1)Increase in distance (of outermost electron)/larger atomic radiusOR(increase in) shielding outweighs nuclear charge (increase) (1)Accept electron at higher energy levelIgnore references to: effective nuclear charge OR nuclear attraction3 (c)(i)Na:Mg:Almetallic (structure)Sigiant atomic (structure)P:S:Cl:Arsimple molecularAll three correct 1 mark1 (ii)strong covalent bonds (1)(throughout the lattice and lots of energy) need tobreak many bonds (1)2

(iii)Aluminium supplies more electrons (per atom)/Al ion ismore highly charged/Al ion is smaller/ Al ion has a highercharge density (1)Accept reverse for NaThe (attractive) forces between the aluminium ions andthe electrons are stronger/require more energy to breakthan in the case of sodium. (1)2Reject any reference to bonding other than metallic bond/ sea of electrons/ delocalised system[11]

27.(a): 44 neutrons (1): 35 protons (1): 36 electrons (1)3 (b)Na2s2 2p6 3s1 (1)Br2s2 2p6 3s2 3p6 3d10 4s2 4p5 (1)Ignore repeat of 1s22Allow subscripts and ignore capital lettersAllow 4s2 3d10 4p5Allow p as pxpypz with 2 in each (c)They have the same (number of protons and) electron(ic) configurationSame (number of protons and)electronic structureSame (number of protons and)electron arrangementsame (number of protons and)number of electronsMUST MENTION ELECTRONS1Reject just Same number of protonsReject just same number of electron shellsReject same number of outer electronsReject same number of electrons in outer shellReject correct answer followed by reference to outer shell scores (0) (d)Mass spectrometer1Allow variations of spellingReject mass spec (1)

(e) (1)= 79.91(1)2nd mark consequential on transcription error data usedCorrect answer with no working scores 2Answer to 4 S.F. with NO units but allow g/mol2 (f)Between the atoms: Covalent (1)Between the molecules :Induced dipole-(induced) dipoleOR dispersion OR London OR van der Waals ORinstantaneous OR Temp dipole (1) (forces)2Accept variations on van der Waals such as de and walls, vdWReject dipole-dipole OR JUST intermolecular forcesReject IDID[11]

28.(a)(i)Enthalpy/heat/ energy required/change to remove 1 electron (1)from each of one mole (1)of gaseous atoms (of an element) (1)Ignore references to gaseous electrons3Accept X(g) X+(g) + e2 marks for the change and the state but not the molAccept isolated atoms in place of gaseousIf incorrect equation given after correct def 1 mark (ii)O+(g) O2+(g) + e()OrO+(g) e() O2+(g)State symbols required1Reject E (for element) in place of O (b)(i)There is a large increase after the removal of 6 electrons (1)Accept large increase before removal of 7th electronAccept (big) jump between 6 and 7(Group) 6 (1) Stand alone(Need to look at diagram for annotation)2 (ii)Sulphur / S / S8Not CQ1

(c)S8+1 mark S81 mark + Stand alone2Accept 32S8+[9]

29.(a)Group 1 / alkali metals (1)(Relatively) large jump / gap / difference between Em1 and Em2 (1)2nd mark dependent on 1st2Accept substantial drop for 1st ionisation energy from Q to R (b)69159000 (kJ mol1) (actual value: 7733 kJ mol1) (1)500730 (kJ mol1) (actual value: 578 kJ mol1) (1)2 (c)Q must be a noble gas /in group 8/0, since Q and R haveconsecutive atomic numbers (and R is in group 1)1Accept Q as it has a very high / the highest first ionisation energy NOT high ionisation energies (generally) (d)R2+(g) R3+(g) + e()((g))symbols and charges (1)state symbols (1)[Mark independently]2Accept R2+ (g) e R3+(g) (e)Outermost electron(s) for an atom of X is /are in a shell furtherfrom the nucleus / shell of higher energy than that of R.1Accept answer based on better shielding from inner electrons[8]

30.(a)

NeutronsElectrons2412Mg

122612Mg14

2412Mg2+

101 mark each number3Accept words or numbers (b)1s2s2p3s3pMg

1s2s2p3s3pCl

Arrows can be for for 2Accept both arrows up or both downReject numbers (c)Mg(s) + Cl2(g) MgCl2(s)Formulae (1)State symbols (1) only if formulae correct or near miss for MgCl2(e.g. MgCl/Mg2Cl)2Accept multiplesAccept Mg2+(Cl)2(s)Reject Mg2++ 2Cl for MgCl2(0 mark)

(d) (1)= 71 (1)Any unit max 12nd mark consequential on fraction provided 70, 72 and 74 used2Accept answer 2 SFReject use of Ar (0 mark)Reject just 71 with no working (0 mark) (e) moles (1)X 30.6 = 2.04 dm3 (1)Answer with no working 1 max2Accept consequential if wrong answer to (d) used.Accept 71 used when (d) incorrectAccept answer 2 SFReject no or incorrect unit of volume (loses 1 mark) (f)Type Metallic(1)Attraction between Mg2+ (1)And (surrounding) sea of electrons/delocalised electrons (1)Stand alone3Accept cations/positive ions /magnesium ionsReject atoms/nuclei/ionsforce between if used instead of attraction

(g)Ionic (1)

Correct charges and number of ions (1)Correct electronic structures (1)Stand alone3Accept diagram without bracketsAccept Mg with no electrons shownie [Mg]2+Reject any suggestion of electrons being sharedReject [Mg]+[17]

31.(a)Penalise lack of nucleus/atom once only in (i) and (ii)Penalise use of element each time it occurs(i)The number of protons in the nucleus of an atom (of anelement)ORThe number of protons in an atom/nucleus (of an element)1Reject the number of protons in an elementReject the number of protons (ii)The number of protons plus the number of neutrons in thenucleus (of an atom)ORnumber of nucleons (in the nucleus of an atom)1Accept and neutrons instead of plus the number ofReject the number of protons plus neutrons in an element

(b)(i)C and L (1)(Group 0 elements) have the highest (first) ionisation energy(of each period) (1)Accept implied e.g. immediately precedes large dropReject high first I.E.Stand alone2Accept group 0 elements have the highest peaks on the graphAccept highest (effective) nuclear charge/highest number of protons in periodReject filled shellReject smallest atomReject same shielding (ii)F (1)Third after noble gas/C (1)Orfirst element in period with p electron (1)2Accept first mini dip after big dropAccept lowest after Group 1/D in same period (1)Accept (in F, e removed from) p orbital is at a higher energy level than s orbital (in E)Reject just electron in p orbitalReject just s orbitals shield p (iii)Increase in (effective) nuclear charge (1)Same shieldingOR same number of electrons in inner shell/orbitals (1)Stand alone2Accept number of protons/atomic numberReject same distance from nucleusReject increased size of nucleusReject same number of shellsReject electrons in same shell[8]

32.(a)Isotope(s)1

(b)401 (c)(i)mass spectrometer1Accept mass spectrometry(ii)(60.2 69 + 39.8 71) 100(1)= 69.796 = 69.8(1)must be 3sf2Accept correct answer with no working (2)Allow g or g mol1 or g/molReject 1, 2, 4 or 5sfUnits of % (1 mark) (d)(i)(1s2) 2s2 2p6 3s2 3p6 (1) 3d10 4s2 4p1 (1)2Accept capitals/ subscripts/ any order (ii)Ga(g) Ga+(g) + e() ((g))or Ga(g) e() ((g)) Ga+(g)Mark independentlyformulae (1)state symbols (1)2Accept Ga1+(g) + e()Reject (s) is wrong take care to distinguish from (g) (iii)B1Accept 579,1979,2963, 6200[10]

33.(a)..2s22p2OR 1s22s22p2OR (1s2)2s22px12py1ALLOW capitals and subscripts1 (b)large gap/jump between 4th and 5th ionisation energies (so fifth in inner shell)1

(c)4 pairs of electrons around C atom (1)all lone pairs shown (1)Mark independently

ALLOW all dots/crosses2Any attempt at an ionic diagram (0) (d)(i)High energy/fast/gun electrons hit/strikeOR bombarded by electrons (1)Removes/knocks out electron (1)2OR equation eg X X+ + e (-) IGNORE state symbolsIf knock out is mentioned, hit/strike is not required in 1st mark (ii)magnetic field/magnet/electromagnet/magnetic plates1 (e)(i)mass of one atom (of the isotope) (1)relative to 1/12th of the mass of (1)a carbon -12 atom (1)OR 2nd and 3rd marks can be awarded as follows:On a scale where a 12C atom (1)has a mass of 12 (NOT grams) (1)Word atom need only be mentioned onceWord mass need only be mentioned onceIf define R.A.Mmax13 (ii)162 IGNORE units1 (iii)(atoms with) same no. of protons (1)NOT same atomic numberdifferent number of electrons loses 1st mark but IGNORE same number of electronsdifferent number of neutrons (1)NOT different mass number2Penalise incorrect reference to number of electrons

(iv)same number of electrons IGNORE same number of protonsOR same electronic configuration/pattern/structureNOT same number in outer orbit1[14]

34.(a)(i)1/l, 0 1/l, 0minus can be either side, sub or superscriptiodine nos correct (1)chlorine nos correct (1)2 (ii)chlorine oxidation number goes down/goes from 0 to 1, so reduced (1)iodine oxidation number goes up/goes from 1 to 0, so oxidised (1)2Mark consequentially on (a)(i) (iii)moles NaI = (1)moles I2 = 0.1 (1)mass of I2 = 0.1 254 = 25.4 (g) (1)OR300g NaI (1) 254g I2 (1)30.0 = 25.4(g) (1)Correct answer with some working (3)Use of atomic numbers 2 maxPenalise wrong units3 (iv)vol = 0.1 24 = 2.4 (dm3)1If not 2.4, check for consequential on (a)(iii) (b)(i)black/grey/grey-black (1)NOT blue-blackNOT purpleIGNORE shiny/silverySolid (1)2

(ii)I(g) I+(g) + e() OR I(g) e(-) I+(g)species (1)state symbols (1) - award state symbols mark only if species correctand in correct place, or if wrong halogen usedIf I2 OR I2 (0)2[12]

35.(a)(i)moles Na = 92 / 23 = 4 = moles NaClmass NaCl = 4 58.5 = 234 (g)Penalise use of atomic numbers onceIncorrect answer scores (1) only if moles (NaCl) mentionedOR23g Na 58.5g NaCl (1)Mass NaCl (1)2 (ii) = 0.40 mol dm3OR g dm3consequential on (a)(i)units required1 (iii)moles chlorine = 2vol = 2 24 = 48 (dm3)Consequential on (a)(i)Correct answer (some working) (2)Correct answer (no working) (1)Incorrect answer scores (1) only if moles of Cl2 mentioned2 (b)Regular pattern or lattice of (sodium) ionsin a sea of electrons / delocalised electronsALLOW cloud of electronselectrons are mobile / free to move (under an appliedpotential and so conduct electricity)NOT free on its own or carry the charge3

(c)(i)Energy (allow enthalpy) required per moleto remove 1 electron (per atom)from gaseous atomsORX(g) X+(g) + eSpecies (1)State symbols (1) only on correct equationElectron affinity defined (0)3 (ii)chlorine has more protons / nucleus more positiveSame shielding / same number of inner electrons/atomicradius less ALLOW outer electron(s) in same shell(so more energy required)OReffective nuclear charge increases (1)2[13]

36.(a)2 (b)Position depends on proton number/ atomic number (not mass) / Aratom has 1 less proton than K atom.IGNORE references to number of protons = number of electrons1 (c)Average = 36 1.34 + 38 0.16 + 40 98.5100(1)= 39.9(1)1 for more or less than 3 SFIGNORE units2 (d)1s2 2s2 2p6 3s2 3p6 Numbers following letters can be subscript or superscript1s and p can be upper or lower case (e)(i)Ar(g) Ar+ (g) + e() ((g))OR Ar(g) e()((g)) Ar+ (g)Symbol of Ar must be correct1

(ii)Potassium value well below sulphur in range 250-750 (1)Low ionisation energy as electron which is removed is moreshielded / further from the nucleus / in a higher energy level (1)NOT just because electron is in fourth shell2 (iii)Sulphur has 4 electrons in (3) p / phosphorus has 3 (1)Plus any one from:Electrons in shared p orbitals repel (so are lost more easily) (1)half-filled sub-shells are (more) stable (1)phosphorus has half-filled sub-shell (1)2 (iv)Chlorine has more protons/greater nuclear charge (1)Shielding unchanged /electrons in same shell/ electrons samedistance from nucleus (1)Could be answered in terms of S having fewer protons2 (f)Argon inert / unreactive so filament cant react/ vaporises less easily/lasts longer (1)1[14]

37.(a)(i)(1s2)2s22p63s23p64s2OR(1s2)2s22p63s23p63d04s2OR(1s2)2s22p63s23p64s23d0ALLOW subscript numbers in place of superscripts 2p6 2px22py22pz2 numbers must be superscript3p6 3px23py23pz2 numbers must be superscriptIGNORE caps1 (b)(i)Energy/ enthalpy / heat energy change / required per mole (1)NOT evolvedfor the removal of 1 electron (1)from gaseous atoms NOT molecules (1)ORX(g) X+(g) + e- states required for 2nd and 3rd marks (2)Can be actual symbol of an elementACCEPT - e(-)3 (ii)(Even though) there is a greater nuclear charge / number of protonsOR nuclear charge increases down the group (1)outer / valency electron(s) further from nucleus NOT shell on its own (1)and more shielded OR more (filled) inner shells/electrons (1)3

(c)(i)Similarity: number of protons (proton number) (1)IGNORE electronsNOT atomic numberDifference: number of neutrons[correct numbers can be given]NOT atomic mass or number of nucleons (1)2 (ii) = 24.3Method (1)Answer must be to 3 SF (1)Correct answer to 3 SF with some working (2)IGNORE g or g mol-1 other wrong units lose a mark2[11]

38.(a)(i)Mg+(g) Mg2+(g) + e()((g)) / Mg+(g) - e()((g)) Mg2+(g)Equation (1)State symbols (1)2nd mark dependent on 1st except e on wrong side OR 1st or 3rd ionisation energy equation quoted OR cumulative 1st and 2nd ionisation energy quoted2(ii)B / b can be shown on graph1 (b)Dots and crosses (1) all dots/ crosses acceptableEnsure that all electrons are being shownCharges (1) 2nd mark independent of 1st2nd F ion and square brackets not essentialALLOW Fl for FIf one of the ions is completely correct (electrons & charge) 1 (out of 2)2[5]

39.(a)(i)Protons = 19 and electrons = 19 (1)neutrons = 20 (1)ACCEPT as words or numbers2(ii)1s22s22p63s23p6(3d0)4s1ALLOW subscriptsMUST be in this order1 (b)(i)MnO4(1) 1(ii)Purple /violet / mauve / lilac / pink colour has moved towards/is at the positive / left-hand electrode / anodeIf purple colour associated with K+ (0)1(iii)Blue colour moves towards the negative / right-hand electrode /cathode (1)The Cu2+/positive copper ion (is blue) (and is attracted to it) (1)ALLOW:Red/brown deposit forms on cathode (1)Cu2+ + 2e(-) Cu or in words (1)OREffervescence at anode (1)4OH - 4e() 2H2O + O2, or in words (1)2[7]

40.(a)(i)The mass of an atom (of the isotope) (1) NOT average mass.relative to 1/12th the mass of a 12C atom ORrelative to 12C = 12 (1) stand alone markAn answer all in moles can get 2 marksAtom need only be mentioned once. If not mentioned 1 (out of 2)2 (ii) Both have 35 protons (1)79Br has 44 neutrons (1)81Br has 46 neutrons (1)3 (b)(79Br79Br)+ (1)(79Br81Br)+ (1)(81Br81Br)+ (1)1 for no charge then check the restIf give 79Br + 79Br etc with or without charge 1 (out of 3)79 + 79all three must be given 1 (out of 3)3[8]

41.(a)Al atom is (1s2) 2s2 2p6 3s2 3p1 (1)Al3+ ion is (1s2) 2s2 2p6 (1)2 (b)The structure is a regular array / lattice of positive ions (1) NOT nucleisurrounded by delocalised/ a sea of electrons (1)1st two marks can be on a diagram(It conducts electricity) because the electrons are mobile. (1)3(c)(i)Energy/enthalpy change per mole (1)For E(g) E+(g) + e() (2)OR equivalent in words3 (ii)In aluminium the outer electron is in the (3)p orbital whereas inmagnesium it is in the (3)s orbital (1) comparison betweenp and s requiredso aluminiums outer electron is in a higher energy (level)ORthe (3)p electron is more shielded (and so less energy is needed to remove it.) (1)2[10]

42.(a)(i)Idea of impact with energyfast electrons strike sample/ high energy/accelerated electrons /electronsfired at sample/ sample bombarded with /blasted with electrons fromelectron gun (1)Removes an electron/ knock out electrons/ eqn X X+ + e (1)2(ii)magnetic field /magnet / electromagnet NOT charged platesALLOW magnetic plates1 (b)(60.4 69) + (39.6 71) / 60.4 + 39.6 (1)= 69.8 (1)69.792 scores 1 (out of 2)2

(c)(i)B (1)mass no. 10 (1)OR10B / B 10 (2)If + is added max (1) ie for mass number2(ii)..2s22p11(iii)BCl3If an equation for formation of BCl3 is given, look for BCl3 and ignorerest1[9]

43.(a)(i)energy/enthalpy/heat energy change per mole (1) Change requiredfor removal of one electron / to form singly positive charged ion (1)from gas atoms (1)Could get 2 marks for X(g) X+ (g) + e3 (ii)increases plus some attempt at an explanation (1)nucleus more positive / more protons/increased charge (1)outer electrons in same shell / same shielding/electrons being lostfrom the same shellOR atoms smaller so greater attraction/need more energy to be removed (1)Decreases 0 (out of 3)3 (b)(i)N(g) + e() N 2(g)species (1)both state symbols (1)2(ii)(energy needed to overcome) repulsion (1) must relate to negativelycharged species.between electron and negative ion (1)ACCEPT negative particles if eqn in (i) correctIf repulsion between electrons coming in and those already thereALLOW 1stmark2[10]

44.1601[1]

45.1s22s22p63s21

46.(a)(i)Metallic (1)

Ions must not be touching and have a single positive charge.2 (ii)

Correct number of electrons on each ion (1)Correct charge on each ion (1)2 (iii)Smaller (with some justification) (1)fewer shells/energy levels (1)increased relative nuclear charge 'pulls' remaining electrons closer tonucleus (1)3 (b)Group 2 (1)Signfficant / large / big increase in IE between 2nd and 3rd electron removed (1)2 (c)Small dip in IE becauseelectron is in same quantum level/shell (1)but is in higher energy sub level/shell (1)2[11]

47.(a)(i)(1s2)2s22p6OR 2s22p22py22pz21 (ii)2s22p63s23p63d104s24p6 / 2s22p63s23p64s23d104p61 (b)Krypton because greater/ stronger (NOT more) van der Waals/London/ dispersion/ temporary or induced dipole forces / attractions (1)Because of larger number of electrons/ extra shell(s) of electrons (1)2

(c)(i)Sample bombarded/ fired at by electrons/ electron gun (1)Knocks out/ loses/ removes electrons from the sampleOr equation (1)2(ii)Electric/electrostatic field/ (negatively) charged plates/ potential difference1(iii)Magnetic field/ (electro)magnet1[8]

48.(a)Weighted/ reference to abundance average mass of atoms/ isotopes(in sample) (1)Relative to (mass of one atom of) 12C (1)2 (b)FF and atomic no.9(1)mass no.19 (1)2 (c)Any (named) group 3 element (1) Big jump between 3rd and 4th I.E. /1st three electrons removed easily./4th electron in lower energy level/ gained stable octet after 3e removed (1)2[6]

49.(a)Moles = 2.20 / 101 (1)Concentration = 0.0218/ 0.05 = 0.436 (mol dm3) but must be in mol dm3 (1)2 (b)(i)Mass = (0.0218 ) 85 (1)=1.85 (g) (1)Answer could be in kg but units must be quoted2 (ii)Vol = (24 ) 0.01089 (1)= 0.261 (dm) (1)Can quote volume in any feasible unitIn (a) and ( b) intermediate values (if stated) and final answers tocalculations must be given to 2 4 s.f.Penalise SF once2 (c)Stability increases followed by an attempt at an explanation (1)because charge density of cation/ metal ion/ group 1 ion decreases OR size increases but charge stays the same (1)so polarises/distorts/ weakens bonds within nitrate/ negative ion/ anion less (1)3

(d) (1) (1)(2:1:3) ie K2CO3 (1)If 19 in first step ie K4CO3 2 (out of 3)3(working must be shown)[12]

50.Si: giant molecular/ atomic/ structureOR macro molecular/ atomic/ structureOR LatticeOR networkOR diagram with a minimum of 5 atoms shown with continuation (1)P: molecular OR exists as P4 (1)Si: covalent bonds to break (1)P: intermolecular forces/ van der Waals forces between moleculesto overcome (1)Therefore more energy to separate silicon atoms (1) dependent on areasonable explanation for Si and P 5[5]

51.(a)(i)Same numbers of protons/electrons (1)Different numbers of neutrons (1)2(ii)X 69/100 + (100 X) 71 /100= 69.8Method (1)\X = 60% Answer (1)2 (b)(i)Ga(g) e() Ga +(g)Entities (1)2states (1)(ii)As the ion becomes more positive it is harder to remove (negative)electrons / same nuclear charge attracting fewer electrons1(iii)An electron is removed from a lower/different quantum shell (1)which is closer to the nucleus (1)NOT shielding arguments2

(c)(i)GaCl3 / Ga2Cl61(ii)Conductivity measurement / electrodes and simple circuit / electrolyse solution (1)(High) reading for electrical conductivity / bulb lights/ high meter reading/ C12 formed (1)Microscope slide, filter paper etc / U-tube method provided detailed 1 maxALLOW AgNO3(aq) (1) white ppt (1)2[12]

52.(a)(i)Weighted average (mass) of 1 atom (1)on a scale in which 1 atom of 12C = 12 units / compared to1/12 atom of 12C (1)2(ii)Number of protons plus / and neutrons or nucleons in a nucleus / an atom.1(iii)Atoms of same atomic number / same proton number (1)which differ in the number of neutrons (1) (in the nucleus)2 (b)(i)Concept of high energy electron collision:Electron bombardment / gun / acceleration / fired (1)knocks off electron / equation showing electron being knocked off (1)2(ii)Positive, +, S+1(iii)Voltage differential across plates / charged plates [plural] /electrostatic field / electric field1 (c)[95.0 32 + 0.76 33 + 4.24 34] / 100 (1)= 32.0924 = 32.09 (1) NOT 32 or 32.102(d)1s2s2p63s3p41[12]

53.(a)Trend - boiling point increases down the group / from He to Xe or Rn (1)Reason number of electrons (and protons) increases (1)Increased strength of van der Waals/ dispersion / London forces / temporarydipoles / induced dipoles / attraction between nucleus and electrons on otheratom (1)3

(b)(i)P or S or Cl / P4, S2, S8, Cl12 / names1(ii)The atoms of silicon are held together by covalent bonds across thewhole structure (1)High energy required (to break bonds) (1) consequential onindication of covalent. Mention of ionic or metallic or van der Waalsforces loses both marks.2 (iii)1.Magnesium ion has larger charge (density) than sodium /magnesium contributes two electrons per atom to the sea ofelectrons. (1)2.Hence magnesium (ions) have greater attraction for (sea of) electronsthan sodium. (1)3.Melting requires energy to overcome this attraction, hencegreater attraction means higher melting temperature (1)This mark is consequential upon the concept of metallic bonding.3[9]

54.(a)31e, 38n, 31pAll correct (2) 2 correct (1)2 (b) (1)= (4140 + 2840)/100= 69.8 (1)-1 for more or less than 3 SF2 (c)Metallic/ metal1[5]

55.(a)(i)(1s2)2s2 2p6 3s2 3p6 4s6 (1)1 (ii)7 (1)1 (b)(i)Ca + Cl2 CaCl2 (1)1 (ii)Ionic (1)1

(iii)1 mark for correct number of electrons on each ion (1)1 mark for correct charges on each ion (1)1 mark for correct ratio of ions (1)3[7]

56.(a)Protons 3 (1)Neutrons 4 (1)Electrons 2 (1)3 (b)Relative atomic mass= (1)6.95 (must be three s.f.) (1)2 (c)Dip Pt / nichrome wire in solid and place in hot/blue flame (1)Na salt gives yellow colour (1)Li salt give deep / magenta red / crimson colour (1)3[8]

57.(a)(i)Energy / enthalpy change per mole (1)required to remove an electron (1)from / mole of gaseous atoms (1)3(ii)The nuclear charge on K is greater than on Na (1)the outer electron is further from the nucleus (1)but there is more shielding around K than Na (1)3

(b)(i)4.56 / 71 (1) = 0.0642 (1)mol2(ii)Answer from (i) - 2 (1) = 0.0321 mol1(iii)Answer from (ii) 24 (1) 0.771 dm31(iv)Answer from (iii) 3/2 (1) 1.16 dm31[11]

58.(a)(i)(46 8 + 47 7.3 + 48 74 + 49 5.5 + 50 5.2) 100 = 47.926 = 47.9Method (1)Correct answer to three significant figures (1)2(ii)mass spectrometer1(b)(i)1s2 2s2 2 p6 3s2 3 p6 (1) 4s2 3d2 OR 3d2 4s2 (1)2(ii)Transition metals /elements OR d block1(c)(i)reduction or redox1(ii)940 2 110 = +720 kJ mol1Method (1)Value (1)Sign and units (1)3(iii)Hess / Law of Conservation of Energy First Law of Thermodynamics1(iv)Carbon monoxide / CO is produced (1)which is toxic / poisonous (1)2[13]

59.(a)Proton + 1 (1)Electron 1/1800 1/2000 or negligible (1)Neutron charge 0 / no charge (1)3Correct p n e in both C and H (1)Notes there are 4 H (1)Correct summation i.e 10p, 10e, 6n (1)3If no or inadequate working 1 mark for 10 p & 10 e1 mark for 6 n. (c)(1s2) 2s22p63s23p5 (1)1 (d)37Cl+charge(stand alone) (1)237 (1)if incorrect number of protons / mass numbershown max 1 for charge (e)(i)S(g) + e- S-(g)species and charges (1)state symbols in part (i) and (ii) equations (1)2

(ii)S(g) S+(g) + eorS(g) e- S+(g) (1)1Species and charge (1)No need to show negative charge on electron.If use X in place of S penalise once only (f)Chlorine nucleus has greater charge / is more positive / has greater number of protons (1)outer electron / electron being removed, is in sameshell / has same shielding (1)2[14]

60.(a)(i)Number of protons + number of neutrons (1)1(ii)(weighted) average / mean mass of one atom (1)relative to one twelfth the mass of carbon-1 2 (atom) / on ascale in which 12C = 12 (1)2 (iii)atoms with same atomic no/ same no of protons/ same element (1)but different numbers of neutrons / mass number (1)2 (b)(24 0.7860) + (25 0.1011) + ( 26 0. 1129) (1)24.33 (1)2[7]

61.(a)(Heat) energy / enthalpy change needed/required per mole (1)to remove an electron (1)from an atom of magnesium in the gas phase (1)For three marks to be awarded there must be some referenceto magnesium in the written answer or in an equation.3 (b)(i)Two/big jumps show three/new/different shells present (1)2 electrons with lowest I.E. in outer shell / first two electrons inouter shell / idea of order of removal (1)then 8 then 2 / shows it is 2.8.2 (1)Reference to s and p type electrons loses final mark becausedata does not show this.The use of orbital/sub shell rather than shell should bepenalised once only.3

(c)(i)1s22s22p63s2 (1)1(ii)Same number of electrons (in all magnesium isotopes) (1)outer electron structure determines chemical properties (1)2[9]

62.(a)(i)

NaMgAlSiPSClArm.p./C:98650660141044119101189structural typegiant / metallicgiant (covalent)/macromolecularSimple / simple molecular /molecular (covalent)(mon)atomic/single atoms2 marks for four correct answers; 1 mark for three correct2 (b)Na largest atom / ion / cationorNa+ smallest charge on ion/ or comparison of the charges on the three ions (1)Sodium has one / fewer delocalised electron others have moreorSodium has one / fewer electrons in metallic bond per atom,others have more (1)melting point low because weaker (metallic) bonding (1)The final mark is for the relation of the bonding to the melting point3 (c)(i)Weak van der Waals forces because Ar atoms have fewelectronsorVery weak /weakest van der Waals forces between Ar atoms (1) -1 (ii)S8 has stronger van der Waals forces than P4 (1)Because it has more electrons/bigger molecules (NOT mass) (1)Explanation of van der Waalsforces rather than nameacceptable2[8]

63.(a)(i)number of protons (in the nucleus)/ proton number (1)not number of electrons or number of protons in an element (1)(ii)Electronic configuration differs from previous element by an electron in a d (sub) shell or orbital / d-shell is filling / d electron is last electron (1)Allow outer electron is d / highest energy electron is d1(iii)Forms at least one ion/compound with partially full / incomplete d sub shell (1)1 (b)1s2 2s2 2p6 3s2 3p6 4s2 3d5 or 3d54s2 (1)1(c)(i)The heat/energy/enthalpy change needed to remove one mole of electrons (1)from (1mole) of gaseous (chlorine) atoms (1)Correct equation i.e. Cl(g) Cl+(g) + e can score second mark.2(ii)Increasing slopes (1)Jump after 7 (1)Jump after 15 (1)Ignore small jumps in the correct places. The points do not need to be joined.3 (d)There are several way of doing this calculation; the following is one way. All other valid ways score full marks43.7/55 = 0.795 56.3/35.5 = 1.59 (1)0.795/0.795 = 1 1.59/0.795 = 2 (1)MnCl2 (1) This is a stand alone markorMnCl2 and some correct working (3)Note:If a candidate gets a formula MnClx where is between 2 and 7 because they have made a chemical error, they can score a maximum of 1 mark. If the error is mathematical they can score a maximum of 2 marks3[12]

64.(a)(i)Fast/high energy/fired/bombard/electrons (electron gun) strike sample atomsKnocking out/ remove electron from sample atom2(ii)Electric field/charged plates/negative plates1

(b)(i)65Cu+1(ii)(2)(different) isotopes1(iii)(63 69.1) + (65 30.9) divided by (69.1 + 30.9) (1) = 63.6/63.62/63.618 (1)2[7]

65.(a)(i)Atomic number: number of protons ( in the nucleus) (1)Mass number: [Total/sum of the)numbers of protons plus/and neutrons (1)2(ii)Na+ or 1123Na+ or a sodium ion1 (b)(i)( 79Br81Br )+ or ( 79Br81Br )+1(ii)Some working or justification (1)50:50 or equivalent (1)2e.g. Because the two peaks at 158 and 162 are the same height (1)the relative abundance of each must be 50%(1) (c)The heat /energy/ enthalpy change/ released per mole of electrons (1)for addition to 1mol of gaseous(bromine) atoms (1)Br(g) + e Br(g) (1)3The word gaseous may be omitted provided the state symbol is present on both sides of the equation / vice versa (d)(i)The heat /energy/ enthalpy change/needed per mol of electrons (1)for removal from 1mol of gaseous(neon) atoms (1)The equation is not asked for but can be used to score the second mark above.2Ne(g) e Ne+(g) (ii)(The first ionisation energy increases as) the nuclear charge increases (1)(Inner shell) shielding remains the same (as nuclear charge increases)/ electrons removed from same energy level/shell (1)2(iii)there is less inner shell shielding in Ne (1)Although there is an increase in the nuclear charge from Ne to Ar (1)ORatomic radius for Ne is smaller than for Ar/ the outer (2p) electron in Ne is closer to the nucleus than the (3p) electron in Ar (1)2[15]

66.(a)(i)electron configuration or 3d64s2 or 4s2or number of outer electrons1(ii)26 protons, 26 electrons, 30 neutronsall 3 (2) any 2 (1)2(iii)atoms (of same element) with same number of protons or same atomic number1different number of neutrons or mass number1 (b)(i)A ionisation not vaporisation1B acceleration1C deflection1D detection1 (ii)(5.8 54) + (91.6 56) + (2.2 57) + (0.33 58) 1001= 55.871[11]