1.	(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  _11^23Na^+ or a sodium ion	1
 
(b)	(i)	( ^79Br^81Br )^+  or  ( _79Br_81Br )^+	1
(ii)	Some working or justification  (1)
50:50 or equivalent  (1)	2
e.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)	3
	The 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.
2
Ne(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)	OR
atomic 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]

2.	(a)	(i)	electron configuration or 3d^64s^2 or 4s^2
or number of outer electrons	1
(ii)	26 protons, 26 electrons, 30 neutrons
all 3  (2)       any 2  (1)	2
(iii)	atoms (of same element) with same number of 
protons or same atomic number	1
different number of neutrons  or mass number	1

(b)	(i)	A  ionisation not vaporisation	1
B  acceleration	1
C  deflection	1
D  detection	1
 
(ii)	(5.8 × 54) + (91.6 × 56) + (2.2 × 57) + (0.33 × 58)
                                   100	1
= 55.87	1
[11]

3.	(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 d	1
(iii)	Forms at least one ion/compound with partially full / incomplete d sub shell (1)
1
 
(b)	1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^5  or  3d^54s^2 (1)	1
(c)	(i)	The heat/energy/enthalpy change needed to remove one mole of electrons (1)
from (1 mole) 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 marks
43.7/55 = 0.795       56.3/35.5  =  1.59 (1)
0.795/0.795  =  1       1.59/0.795  =  2 (1)
MnCl_2 (1)  This is a stand alone mark
or
MnCl_2 and some correct working (3)
Note:
If a candidate gets a formula MnCl_x 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 marks
3
[12]

4.	(a)	(i)	•	Fast/high energy/fired/bombard/electrons (electron gun) strike sample atoms
•	Knocking out/ remove electron from sample atom	2
(ii)	Electric field/charged plates/negative plates	1
 
(b)	(i)	^65Cu^+	1
(ii)	(2)(different) isotopes	1
(iii)	(63 × 69.1) + (65 × 30.9) divided by (69.1 + 30.9) (1) 
= 63.6/63.62/63.618 (1)	2
[7]

5.	(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 a
scale 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]

6.	(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 reference
to 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 in
outer 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 because
data does not show this.
The use of orbital/sub shell rather than shell should be
penalised once only.	3
 
(c)	(i)	1s^22s^22p^63s^2 (1)	1
(ii)	Same number of electrons (in all magnesium isotopes) (1)
outer electron structure determines chemical properties (1)	2
[9]

7.	(a)	(i)
| Na | Mg | Al | Si | P | S | Cl | Ar
m.p./°C: | 98 | 650 | 660 | 1410 | 44 | 119 | –101 | –189

structural type

giant / metallic

giant (covalent)/
macromolecular

Simple / simple molecular /
molecular (covalent)

(mon)atomic
/single atoms

	2 marks for four correct answers; 1 mark for three correct	2
 
(b)	Na largest atom / ion / cation
or
Na^+ smallest charge on ion/ or comparison of the charges on the three ions (1)
Sodium has one / fewer delocalised electron others have more
or
Sodium 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 point	3
 
(c)	(i)	Weak van der Waals’ forces because Ar atoms have few
electrons
or
Very weak /weakest van der Waals’ forces between Ar atoms (1) -	1

(ii)	S_8 has stronger van der Waals’ forces than P_4 (1)
Because it has more electrons/bigger molecules (NOT mass) (1)
Explanation of van der Waals’forces rather than name
acceptable	2
[8]

8.	(a)	Proton + 1 (1)
Electron 1/1800 → 1/2000 or ‘negligible’ (1)
Neutron charge 0 / no charge (1)	3
	Correct p n e in both C and H (1)
Notes there are 4 H (1)
Correct summation i.e 10p, 10e, 6n (1)	3
If no or inadequate working 1 mark for 10 p & 10 e
1 mark for 6 n.
 
(c)	(1s^2) 2s^22p^63s^23p^5 (1)	1
 
(d)	^37Cl^+
charge(stand alone) (1)	2
37 (1)
if incorrect number of protons / mass number
shown 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) + e^–
or
S(g) – e^− → S^+(g) (1)	1
Species 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 same
shell / has same shielding (1)	2
[14]

9.	(a)	(i)	(1s^2)2s^2 2p^6 3s^2 3p^6 4s^6 (1)	1
 
(ii)	7 (1)	1
 
(b)	(i)	Ca + Cl_2 → CaCl_2 (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]

10.	(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]

11.	(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)mol	2
(ii)	Answer from (i) − 2 (1) = 0.0321 mol	1
(iii)	Answer from (ii) × 24 (1) 0.771 dm^3	1
(iv)	Answer from (iii) × 3/2 (1) 1.16 dm^3	1
[11]

12.	(a)	(i)	(46 × 8 + 47 × 7.3 + 48 × 74 + 49 × 5.5 + 50 × 5.2) ÷ 100      = 47.926
		 = 47.9
	Method (1)
Correct answer to three significant figures (1)		2
(ii)	mass spectrometer	1
(b)	(i)	1s^2 2s^2 2 p^6 3s^2 3 p^6 (1) 4s^2 3d^2   OR   3d^2 4s^2 (1)	2
(ii)	Transition metals /elements   OR   d block	1
(c)	(i)	reduction or redox	1
(ii)	940 – 2 × 110 = +720 kJ mol^–1
	Method (1)
Value (1)
Sign and units (1)	3
(iii)	Hess / Law of Conservation of Energy First Law of Thermodynamics	1
(iv)	Carbon monoxide / CO is produced (1)
which is toxic / poisonous (1)	2
[13]

13.	(a)	(i)	Weighted average (mass) of 1 atom (1)
on a scale in which 1 atom of ^12C = 12 units / compared to
1/12 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 field	1

(c)	[95.0 × 32 + 0.76 × 33 + 4.24 × 34] / 100 (1)
= 32.0924 = 32.09 (1) NOT 32 or 32.10	2
(d)	1s²2s²2p^63s²3p^4	1
[12]

14.	(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 / temporary
dipoles / induced dipoles / attraction between nucleus and electrons on other
atom (1)	3
 
(b)	(i)	P or S or Cl / P_4, S_2, S_8, Cl_12 / names	1
(ii)	•	The atoms of silicon are held together by covalent bonds across the
	whole structure (1)
•	High energy required (to break bonds) (1) consequential on
	indication of covalent. Mention of ionic or metallic or van der Waals’
	forces loses both marks.	2
 
(iii)	•	1.	Magnesium ion has larger charge (density) than sodium /
		magnesium contributes two electrons per atom to the ‘sea’ of
		electrons. (1)
•	2.	Hence magnesium (ions) have greater attraction for (sea of) electrons
	than sodium. (1)
•	3.	Melting requires energy to overcome this attraction, hence
	greater attraction means higher melting temperature (1)
	This mark is consequential upon the concept of metallic bonding.	3
[9]

15.	(a)	31e, 38n, 31p
All correct → (2)
   2 correct → (1)	2
 
(b)	 (1)
= (4140 + 2840)/100
= 69.8 (1)
-1 for more or less than 3 SF	2
 
(c)	Metallic/ metal	1
[5]

16.	(a)	(i)	(1s^2)2s^22p^6
OR   2s^22p_×^22p_y^22p_z^2	1
 
(ii)	2s^22p^63s^23p^63d^104s^24p^6 / 2s^22p^63s^23p^64s^23d^104p^6	1
 
(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 sample
Or equation (1)	2
(ii)	Electric/electrostatic field/ (negatively) charged plates/ potential 
difference	1
(iii)	Magnetic field/ (electro)magnet	1
[8]

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

18.	(a)	Moles = 2.20 / 101 (1)
Concentration = 0.0218/ 0.05 = 0.436 (mol dm^–3) but must be in mol dm^–3 (1)	2
 
(b)	(i)	Mass = (0.0218 ×) 85 (1)
=1.85 (g) (1)
Answer could be in kg but units must be quoted	2

(ii)	Vol = (24 ×) 0.01089 (1)
= 0.261 (dm³) (1)
Can quote volume in any feasible unit
In (a) and ( b) intermediate values (if stated) and final answers to
calculations must be given to 2 – 4 s.f.
Penalise SF once	2
 
(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 K_2CO_3 (1)
If ÷ 19 in first step ie K_4CO_3   2 (out of 3)	3
(working must be shown)
[12]

19.	Si: giant molecular/ atomic/ structure
OR macro molecular/ atomic/ structure
OR Lattice
OR network
OR diagram with a minimum of 5 atoms shown with continuation (1)
	P: molecular OR exists as P_4 (1)
	Si: covalent bonds to break (1)
	P: intermolecular forces/ van der Waals’ forces between molecules
to overcome (1)
	Therefore more energy to separate silicon atoms (1) – dependent on a
reasonable explanation for Si and P 	5
[5]

20.	(a)	(i)	Same numbers of protons/electrons (1)
Different numbers of neutrons (1)	2
(ii)	X × 69/100 + (100 – X) × 71 /100
= 69.8	Method (1)
∴X = 60%    Answer (1)	2

(b)	(i)	Ga(g) – e^(–) → Ga ^+(g)
Entities (1)	2
states (1)
(ii)	As the ion becomes more positive it is harder to remove (negative)
electrons / same nuclear charge attracting fewer electrons	1
(iii)	An electron is removed from a lower/different quantum shell (1)
which is closer to the nucleus (1)
NOT shielding arguments	2
 
(c)	(i)	GaCl_3 / Ga_2Cl_6	1
(ii)	Conductivity measurement / electrodes and simple circuit / 
electrolyse solution (1)
(High) reading for electrical conductivity / bulb lights/ high meter
 reading/ C1_2 formed (1)
Microscope slide, filter paper etc / U-tube method –
provided detailed 1 max
ALLOW AgNO_3(aq) (1) white ppt (1)	2
[12]

21.	(a)	(i)	Idea of impact with energy
fast electrons strike sample/ high energy/accelerated electrons /electrons
fired at sample/ sample bombarded with /blasted with electrons from
electron gun (1)
Removes an electron/ knock out electrons/ eqn X → X^+ + e^– (1)	2
(ii)	magnetic field /magnet / electromagnet NOT charged plates
ALLOW magnetic plates	1
 
(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)
OR
^10B / B ^10 (2)
If + is added max (1) ie for mass number	2
(ii)	..2s^22p^1	1
(iii)	BCl_3
If an equation for formation of BCl_3 is given, look for BCl_3 and ignore
rest	1
[9]

22.	(a)	(i)	energy/enthalpy/heat energy change per mole (1) Change ≡ required
for removal of one electron / to form singly positive charged ion (1)
from gas atoms (1)
Could get 2 marks for X(g) → X^+ (g) + e^–	3
 
(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 lost
from the same shell
OR 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 negatively
charged species.
	between electron and negative ion (1)
ACCEPT “negative particles” if eqn in (i) correct
If “repulsion between electrons coming in and those already there”
ALLOW 1^stmark	2
[10]

23.	160	1
[1]

24.	1s^22s^22p^63s^2	1

25.	(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 to
nucleus (1)	3
 
(b)	Group 2 (1)
Signfficant / large / big increase in IE between 2^nd and 3^rd electron removed (1)	2
 
(c)	Small dip in IE because
electron is in same quantum level/shell (1)
but is in higher energy sub level/shell (1)	2
 
(d)	(i)	Similarity
Similar/same trend across period/down a group (1)
Difference
	Values for boiling point would be higher/height of bars bigger (1)	2
(ii)	Density/atomic volume/electrical conductivity/electronegativity/
enthalpy or heat of vaporization	1
[14]

26.	(a)	(i)	The mass of an atom (of the isotope) (1) – NOT average mass….
relative to 1/12^th the mass of a ^12C atom 
OR
relative to ^12C = 12 (1) – stand alone mark
An answer all in moles can get 2 marks
Atom 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)	(^79Br–^79Br)^+ (1)
(^79Br–^81Br)^+ (1)
(^81Br–^81Br)^+ (1)
–1 for no charge then check the rest
If give ^79Br + ^79Br etc with or without charge 1 (out of 3)
79 + 79…all three must be given 1 (out of 3)	3
[8]

27.	(a)	Al atom is (1s^2) 2s^2 2p^6 3s^2 3p^1 (1)
Al^3+ ion is (1s^2) 2s^2 2p^6 (1)	2
 
(b)	The structure is a regular array / lattice of positive ions (1) NOT nuclei
surrounded by delocalised/ ‘a sea of’ electrons (1)
1^st 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 words	3
 
(ii)	In aluminium the outer electron is in the (3)p orbital whereas in
magnesium it is in the (3)s orbital (1) – comparison between
p and s required
	so aluminium’s outer electron is in a higher energy (level)
OR
the (3)p electron is more shielded (and so less energy is needed to remove
 it.) (1)	2
[10]

28.	(a)	(i)	(1s^2)2s^22p^63s^23p^64s^2
OR
(1s^2)2s^22p^63s^23p^63d^04s^2
OR
(1s^2)2s^22p^63s^23p^64s^23d^0
ALLOW subscript numbers in place of superscripts 
	2p^6 ≡ 2p_x^22p_y^22p_z^2  numbers must be superscript
3p^6 ≡ 3p_x^23p_y^23p_z^2  numbers must be superscript
IGNORE caps	1

(b)	(i)	Energy/ enthalpy / heat energy change / required per mole (1)
NOT evolved
for the removal of 1 electron (1)
from gaseous atoms NOT molecules (1)
OR
X(g) → X^+(g) + e^- states required   for 2^nd and 3^rd marks    (2)
Can be actual symbol of an element
ACCEPT - e^(-)	^3
 
(ii)	(Even though) there is a greater nuclear charge / number of protons
OR 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 electrons
NOT atomic number
	Difference: number of neutrons
[correct numbers can be given]
NOT atomic mass or number of nucleons (1)	2
 
(ii)	 = 24.3
	Method (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 mark	2
[11]

29.	(a)	(i)	Mg^+(g) → Mg^2+(g) + e^(−)((g)) / Mg^+(g) - e^(−)((g)) → Mg^2+(g)
	Equation (1)
State symbols (1)
2^nd mark dependent on 1^st except
– e on wrong side OR
– 1^st or 3^rd ionisation energy equation quoted OR
– cumulative 1^st and 2^nd ionisation energy quoted	2
(ii)	B / b – can be shown on graph	1
 
(b)	
	Dots and crosses (1) – all dots/ crosses acceptable
Ensure that all electrons are being shown
	Charges (1) – 2^nd mark independent of 1^st
	2^nd F^− ion and square brackets not essential
ALLOW “Fl” for “F”
If one of the ions is completely correct (electrons & charge) 1 (out of 2)	2
[5]

30.	(a)	(i)	Protons = 19 and electrons = 19 (1)
	neutrons = 20 (1)
	ACCEPT as words or numbers	2
(ii)	1s^22s^22p^63s^23p^6(3d^0)4s^1
ALLOW subscripts
MUST be in this order	1
 
(b)	(i)	MnO_4^(1) ^−	1
(ii)	Purple /violet / mauve / lilac / pink colour has moved towards/
is at the positive / left-hand electrode / anode
If purple colour associated with K^+ (0)	1
(iii)	Blue colour moves towards the negative / right-hand electrode /cathode (1)
The Cu^2+/positive copper ion (is blue) (and is attracted to it) (1)
ALLOW:
Red/brown deposit forms on cathode (1)
Cu^2+ + 2e^(-) Cu or in words (1)
OR
Effervescence at anode (1)
4OH^– - 4e^(–) 2H_2O + O_2, or in words (1)	2
[7]

31.	(a)	(i)	moles Na = 92 / 23 = 4 = moles NaCl
mass NaCl = 4 × 58.5 = 234 (g)
Penalise use of atomic numbers once
Incorrect answer scores  (1) only if moles (NaCl) mentioned
	OR
23g Na ⇒ 58.5g NaCl  (1)
Mass NaCl  (1)
	2
 
(ii)	 = 0.40 mol dm^–3	OR	 g dm^–3
	consequential on (a)(i)
units required	1
 
(iii)	moles chlorine = 2
vol = 2 × 24 = 48 (dm^3)
Consequential on (a)(i)
	Correct answer (some working)  (2)
Correct answer (no working)  (1)
Incorrect answer scores  (1) only if moles of Cl_2 mentioned	2
 
(b)	Regular pattern or lattice of (sodium) ions
	in a sea of electrons / delocalised electrons
ALLOW “cloud of electrons”
	electrons are mobile / free to move (under an applied
potential and so conduct electricity)
NOT ‘free’ on its own or carry the charge	3
 
(c)	(i)	Energy (allow enthalpy) required per mole
to remove 1 electron (per atom)
from gaseous atoms
OR
X(g) → X^+(g) + e
Species  (1)
State symbols  (1) – only on correct equation
Electron affinity defined  (0)	3

(ii)	chlorine has more protons / nucleus more positive
	Same shielding / same number of inner electrons/atomic
radius less     ALLOW outer electron(s) in same shell
(so more energy required)
	OR
effective nuclear charge increases  (1)	2
[13]

32.	(a)		2
 
(b)	Position depends on proton number/ atomic number (not mass) / Ar
atom has 1 less proton than K atom.
IGNORE references to number of protons = number of electrons	1
 
(c)	Average = 36 × 1.34 + 38 × 0.16 + 40 × 98.5
100	(1)
= 39.9	(1)
	–1 for more or less than 3 SF
IGNORE units	2
 
(d)	1s^2 2s^2 2p^6 3s^2 3p^6 
Numbers following letters can be subscript or superscript	1
s 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 correct	1
 
(ii)	Potassium value well below sulphur in range 250-750  (1)
Low ionisation energy as electron which is removed is more
shielded / further from the nucleus / in a higher energy level  (1)
NOT just ‘because electron is in fourth shell’	2
 
(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 same
distance from nucleus  (1)
Could be answered in terms of S  having fewer protons	2
 
(f)	Argon inert / unreactive so filament can’t react/ vaporises less easily/
lasts longer  (1)	1
[14]

33.	(a)	..2s^22p^2	OR 1s^22s^22p^2	OR (1s^2)2s^22p_x^12p_y^1
ALLOW capitals and subscripts		1
 
(b)	large gap/jump between 4^th and 5^th 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/crosses	2
Any attempt at an ionic diagram (0)
 
(d)	(i)	High energy/fast/gun electrons hit/strike
OR bombarded by electrons (1)
	Removes/knocks out electron (1)	2
OR equation eg X → X^+ + e ^(−) IGNORE state symbols
If knock out is mentioned, hit/strike is not required in 1^st mark
 
(ii)	magnetic field/magnet/electromagnet/magnetic plates	1
 
(e)	(i)	mass of one atom (of the isotope) (1)
relative to 1/12^th of the mass of (1)
a carbon -12 atom (1)
	OR 2^nd and 3^rd 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 once
Word “mass” need only be mentioned once
If define R.A.M……max1	3
 
(ii)	162 IGNORE units	1
 
(iii)	(atoms with) same no. of protons (1)
NOT same atomic number
“different number of electrons” loses 1^st mark but IGNORE “same number of electrons”
	different number of neutrons (1)
NOT different mass number	2
Penalise incorrect reference to number of electrons
 
(iv)	same number of electrons         IGNORE “same number of protons”
	OR same electronic configuration/pattern/structure
NOT same number in outer orbit	1
[14]

34.	(a)	(i)	–1/–l, 0           –1/–l, 0
minus can be either side, sub or superscript
	iodine no’s correct (1)
chlorine no’s 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)	2
Mark consequentially on (a)(i)
 
(iii)	moles NaI =  (1)
	moles I_2 = 0.1 (1)
	mass of I_2 = 0.1 × 254 = 25.4 (g) (1)
	OR
300g NaI (1) → 254g I_2 (1)
	30.0 × = 25.4(g) (1)
	Correct answer with some working (3)
Use of atomic numbers 2 max
Penalise wrong units	3
 
(iv)	vol = 0.1 × 24 = 2.4 (dm^3)	1
If not 2.4, check for consequential on (a)(iii)

(b)	(i)	black/grey/grey-black (1)
NOT blue-black
NOT purple
IGNORE shiny/silvery
Solid (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 correct
and in correct place, or if wrong halogen used
If I_2 OR ½I_2 (0)	2
[12]

35.	(a)
| Neutrons | Electrons
24 12Mg | | 12

26
12Mg

14

24 12Mg^2+ | | 10
	1 mark each number	3
Accept words or numbers
 
(b)
		1s	2s	2p	3s	3p
Mg | | | | | ↑↓ | ↑↓ | ↑↓ | | ↑↓ | | | |
		1s	2s	2p	3s	3p
Cl | | | | | ↑↓ | ↑↓ | ↑↓ | | ↑↓ | | ↑↓ | ↑↓ | ↑
	Arrows can be
 for ↑
 for ↓	2
Accept both arrows up or both down
Reject numbers

(c)	Mg(s) + Cl_2(g) → MgCl_2(s)
	Formulae (1)
State symbols (1) – only if formulae correct or near miss for MgCl_2
(e.g. MgCl/Mg_2Cl)	2
Accept multiples
Accept Mg^2+(Cl^–)_2(s)
Reject “Mg^2++ 2Cl^–” for MgCl_2
(0 mark)
 
(d)	 (1)
= 71 (1)
Any unit max 1
2^nd mark consequential on fraction provided 70, 72 and 74 used	2
Accept answer ≥ 2 SF
Reject use of Ar (0 mark)
Reject just “71” with no working (0 mark)
 
(e)	 moles (1)
	X 30.6 = 2.04 dm^3 (1)
Answer with no working 1 max	2
Accept consequential if wrong answer to (d) used.
Accept 71 used when (d) incorrect
Accept answer ≥ 2 SF
Reject no or incorrect unit of volume (loses 1 mark)
 
(f)	Type – Metallic(1)
	Attraction between Mg^2+ (1)
	And (surrounding) sea of electrons/delocalised electrons (1)
	Stand alone	3
Accept cations/positive ions /magnesium ions
Reject atoms/nuclei/ions
“force between” if used instead of “attraction”

(g)	Ionic (1)

	Correct charges and number of ions (1)
Correct electronic structures (1)
Stand alone	3
Accept diagram without brackets
Accept Mg with no electrons shown
ie [Mg]^2+
Reject any suggestion of electrons being shared
Reject [Mg^•]^+
[17]

36.	(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 an
element)
OR
The number of protons in an atom/nucleus (of an element)	1
Reject the number of protons in an element
Reject the number of protons
 
(ii)	The number of protons plus the number of neutrons in the
nucleus (of an atom)
OR
number of nucleons (in the nucleus of an atom)	1
Accept “and neutrons” instead of “plus the number of……”
Reject 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 drop
Reject high first I.E.
	Stand alone	2
Accept group 0 elements have the highest peaks on the graph
Accept highest (effective) nuclear charge/highest number of protons in period
Reject filled shell
Reject smallest atom
Reject same shielding
 
(ii)	F (1)
	Third after noble gas/C (1)
	Or
first element in period with p electron (1)	2
Accept first mini dip after big drop
Accept 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 orbital”
Reject just “s orbitals shield p”
 
(iii)	Increase in (effective) nuclear charge (1)
	Same shielding
OR same number of electrons in inner shell/orbitals (1)
	Stand alone	2
Accept number of protons/atomic number
Reject same distance from nucleus
Reject increased size of nucleus
Reject same number of shells
Reject electrons in same shell
[8]

37.	(a)	Isotope(s)	1

(b)	40	1
 
(c)	(i)	mass spectrometer	1
Accept mass spectrometry
(ii)	(60.2 × 69 + 39.8 × 71) ÷ 100	(1)
= 69.796 = 69.8	(1)
must be 3sf		2
Accept correct answer with no working (2)
Allow g or g mol^–1 or g/mol
Reject 1, 2, 4 or 5sf
Units of % (–1 mark)
 
(d)	(i)	(1s^2) 2s^2 2p^6 3s^2 3p^6 (1) 3d^10 4s^2 4p^1 (1)	2
Accept capitals/ subscripts/ any order
 
(ii)	Ga(g) → Ga^+(g) + e^(–) ((g))
or Ga(g) – e^(–) ((g)) → Ga^+(g)
	Mark independently
formulae (1)
state symbols (1)	2
Accept Ga^1+(g) + e^(–)
Reject (s) is wrong – take care to distinguish from (g)
 
(iii)	B	1
Accept 579,1979,2963, 6200
[10]

38.	(a)	: 44 neutrons (1)
	: 35 protons (1)
	: 36 electrons (1)	3

(b)	Na	2s^2 2p^6 3s^1 (1)
	Br	2s^2 2p^6 3s^2 3p^6 3d^10 4s^2 4p^5 (1)
	Ignore repeat of 1s^2	2
Allow subscripts and ignore capital letters
Allow 4s^2 3d^10 4p^5
Allow p as pxpypz with 2 in each
 
(c)	They have the same (number of protons and) electron(ic) configuration
Same (number of protons and)electronic structure
Same (number of protons and)electron arrangement
same (number of protons and)number of electrons
MUST MENTION ELECTRONS	1
Reject ‘just‘ Same number of protons
Reject ‘just’ same number of electron shells
Reject same number of outer electrons
Reject same number of electrons in outer shell
Reject correct answer followed by reference to outer shell scores (0)
 
(d)	Mass spectrometer	1
Allow variations of spelling
Reject mass spec (1)
 
(e)	 (1)
= 79.91(1)
2^nd mark consequential on transcription error data used
Correct answer with no working scores 2
Answer to 4 S.F. with NO units but allow g/mol	2
 
(f)	Between the atoms: Covalent (1)
	Between the molecules :Induced dipole-(induced) dipole
OR dispersion OR London OR van der Waals OR
instantaneous OR Temp dipole – (1) (forces)	2
Accept variations on van der Waals such as de and walls, vdW
Reject dipole-dipole OR ‘JUST’ intermolecular forces
Reject ID–ID
[11]

39.	(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 electrons	3
Accept X(g) → X^+(g) + e
2 marks for the change and the state but not the mol
Accept isolated atoms in place of gaseous
If incorrect equation given after correct def – 1 mark
 
(ii)	O^+(g) → O^2+(g) + e^(–)
Or
O^+(g) – e^(–) → O^2+(g)
State symbols required	1
Reject 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 7^th electron
Accept (big) jump between 6 and 7
	(Group) 6 (1) Stand alone
	(Need to look at diagram for annotation)	2
 
(ii)	Sulphur / S / S_8
	Not CQ	1
 
(c)	S_8^+
1 mark ‘S_8’
1 mark ‘^+’ Stand alone	2
Accept ^32S_8^+
[9]

40.	(a)	Group 1 / alkali metals (1)
(Relatively) large “jump” / gap / difference between Em_1 and Em_2 (1)
2^nd mark dependent on 1^st	2
Accept substantial drop for 1^st ionisation energy from Q to R
 
(b)	6915–9000 (kJ mol^–1) (actual value: 7733 kJ mol^–1) (1)
	500–730 (kJ mol^–1) (actual value: 578 kJ mol^–1) (1)	2
 
(c)	Q must be a noble gas /in group 8/0, since Q and R have
consecutive atomic numbers (and R is in group 1)	1
Accept Q as it has a very high / the highest first ionisation energy NOT “high ionisation energies” (generally)
 
(d)	R^2+(g) → R^3+(g) + e(^–)((g))
symbols and charges (1)
state symbols (1)
[Mark independently]	2
Accept R^2+ (g) – e^– → R^3+(g)
 
(e)	Outermost electron(s) for an atom of X is /are in a shell further
from the nucleus / shell of higher energy than that of R.	1
Accept answer based on “better shielding” from inner electrons
[8]

41.	(a)	(i)	Copper
…….3d^104s^1	1
Accept subscripts/ignore capitals 4s inside 3d
Reject 3d^94s^2
(ii)	Bromide ion
…….3d^104s^24p^6	1
Accept subscript/ignore capitals 4s inside 3d
Reject 4p inside 3d
 
(b)	The average mass (taking into account the abundance of each isotope)
of the atoms (of that element) (1)
	relative to 1/12th the (mass of a)
carbon 12 atom
Or
relative to ^12C = 12 (exactly) (1)
second mark stand alone	2
Accept weighted/mean in place of average
Atoms must be mentioned at least once to score (2)
Accept average mass of a mole of atoms of an element relative to 1/12^th mole of C^12 / relative to one mole of ^12C = 12 (exactly) (2)

(c)	 (1)
= 63.55 (1)
must be to 2 decimal places
	cq only on transcription error e.g.
69.71 provided answer to 2 d.p.	2
Accept 63.54 with some working scores (1)
Correct answer alone scores (2
Answer should have no unit, but allow unit of “g mol^–1” but not “grams” or “g”
 
(d)	(i)	
Cu | C | O | H
0.906 | 0.450 | 2.26 | 0.900
2.01 | 1 | 5.02 | 2.00
Use of atomic number scores 0
	Empirical formula Cu_2CO_5H_2
(1) for dividing by atomic mass
(1) stating empirical formula	2
Correct answer without working scores (2)
 
(ii)	Empirical formula mass = 221 = M_r
Molecular formula Cu_2CO_5H_2
	Must show use of 221	1
If use atomic number in (i) allow mark for Cu_2CO_5H and 220
Allow any formula that adds up to the correct molecular formula
 
(e)	(Highest = ^65Cu + 2 ^37Cl) = 139 (1)
(Lowest = ^63Cu + 2 ^35Cl) = 133 (1)
Ignore units	2
[11]

42.	(a)	Energy/Enthalpy/heat change per mole for the (1)
Accept “required” instead of “change”
	Removal of one electron (per atom) (1)
	From 1 mole of gaseous atoms (1)
	If wrong equation given with a correct definition (max 2)	3
X(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 radius
OR
(increase in) shielding outweighs nuclear charge (increase) (1)
Accept electron at higher energy level
	Ignore references to: effective nuclear charge OR nuclear attraction	3
 
(c)	(i)	Na:Mg:Al
metallic (structure)
	Si
giant atomic (structure)
	P:S:Cl:Ar
simple molecular
All three correct 1 mark	1
 
(ii)	strong covalent bonds (1)
	(throughout the lattice and lots of energy) need to
break many bonds (1)	2
 
(iii)	Aluminium supplies more electrons (per atom)/Al ion is
more highly charged/Al ion is smaller/ Al ion has a higher
charge density (1)
Accept reverse for Na
	The (attractive) forces between the aluminium ions and
the electrons are stronger/require more energy to break
than in the case of sodium. (1)	2
Reject any reference to bonding other than metallic bond/ sea of electrons/ delocalised system
[11]

43.	(i)	Electrons have opposite spin	1
Reject a paired spin of the electrons
Reject to show they repel each other
Reject going in different directions
Reject due to reverse spin
Reject moving in opposite directions
 
(ii)	Start from n = 3 energy level and going upwards at least
to another energy level (1)
End at or just above n = ∞ energy level (1)	2
Reject arrow into writing
 
(iii)	No because energy levels split into two (1)
(2)s and (2)p (with the 2p higher than the 2s) (1)	2
Accept no because there are 2s and 2p (1)
Accept sublevels (1) /Subshells
Reject no because increasingly hard to remove successive electrons
 
(iv)	1 electron in the n = 4 energy level and
8 electrons in the n = 3 energy level	1
Accept 2,8,8,1 for potassium
Accept n = 3 full, n = 4 1 electron
Reject one more level of electrons
Reject an extra full energy level
Reject more electrons in n=3
[6]

44.	(a)	(i)	High energy/fast/gun electrons hit/strike
OR bombarded by electrons (1)
	Removes/knocks out /causes loss of electron OR equation e.g.
X → X^+ + e^(–)
OR
X + e → X^+ + 2e (1)
IGNORE state symbols
If knock out is mentioned, hit/strike is not required in 1^st mark	2
Any suggestion that a negative ion is produced score zero overall
Reject if just “forms a cation/positive ion”, not sufficient for second mark

(ii)	Mass (1)
Accept weight
	Charge (1)
Accept Mass: charge ratio
OR m/e
OR m/z (1)
	Ignore the following:
speed
kinetic energy
size/volume
radius
charge density
density	2
 
(b)	1^st mark (stand alone)
The mass of an atom (of the isotope) (1)
	2^nd mark (stand alone)
Relative to 1/12^th the mass of a ^12C (atom)
OR
Relative to ^12C =
12(exactly)
OR
On a scale where C^12 has a mass of 12 (1)
	If ‘atom’ missing from 1^st mark it can score if mentioned in 2^nd mark	2
Accept
1^st mark
The mass of a mole of the isotope (1)
2^nd mark
Relative to 1/12^th the mass of a mole of ^12C
OR
On a scale where a mole of C^12 has a mass of 12 g (1)
Must mention the word ‘mole’ at least once in these definitions
Answer must be either consistently atoms or moles in order to be awarded both
Reject average mass/weighted average/
Reject element instead of isotope

(c)	[(49.95 × 4.345) + (51.94 × 83.79) + (52.94 × 9.501) +
(53.94 × 2.364)]/100 (1)
= 51.9958
= 52.00 must be to 4 SF (1)
	Correct answer to 4SF with no working (2)
Should not have units but allow g mol^–1
Allow error carried forward only on transcription error
of mass or percentage	2
Accept 51.99 scores (1) not (2)
Reject 52
Reject 52.0
Reject 52.00 g
 
(d)	
1s | 2s | 2p | 3s | 3p | 3d | 4s
| | | | | ↑↓ | ↑↓ | ↑↓ | ↑↓ | ↑↓ | ↑ | ↑ | ↑ | ↑ | ↑↓
	2 marks for fully correct configuration
1 mark if 26 electrons with 2 in 4s but the 3d electrons shown as pairs
	Ignore the way the arrow heads point in the singly occupied 3d boxes.
	Allow half arrows  or | or ↑ or any combination in any box	2
Accept vertical lines in place of arrows 1 max
[10]

45.	(a)

General increase, starting with carbon above boron (1)
	Dip from N to O only (1)	2
Accept lines joining points do not need to be drawn in.
Accept a very small drop from N to O
 
(b)	•	The nuclear charge/proton number increases / becomes more positive (1)
•	The (inner shell) shielding is the same/same number of inner shell
electrons/ no or little increase in shielding (1)
	Either
•	Outer electron closer to nucleus /atomic radius decreases /size
of atom decreases
	Or
•	electrons being removed are in same shell
	Or
•	Outer electrons are in same shell (1)	3
Reject Atomic Number increasing
 
(c)	In boron the extra electron is in a p orbital /new sub-shell (1)
	Either
Which has extra shielding (by the s orbital electrons)
OR
Which is at a higher energy (level than the s orbital in Be) (1)	2
Accept reverse argument for beryllium
Reject shell for sub-shell
Reject answers that refer to full shell being left do not score second mark
Further from the nucleus
[7]

46.	(i)	112	1
(ii)	 (1)
= 190.3 (1)
	Correct answer with no working (2)
Ignore units	2
Accept 190.34/190.342 with no working = max 1
Reject 190
Reject 190.34
Reject 190.342
[3]

47.	B
[1]

48.	C
[1]

49.	B
[1]

50.	D
[1]

51.	B
[1]

52.	(a)	A	1
 
(b)	B	1
 
(c)	D	1
[3]

53.	(a)	C	1
 
(b)	D	1
 
(c)	A	1
 
(d)	D	1
[4]

54.	(a)	CuCO_3(s) + H_2SO_4(aq) → CO_2(g) + CuSO_4(aq) + H_2O(l)	1
 
(b)	B	1

(c)	(i)	(0.025 × 123.5) × 1.1 = (1)
	3.396/ 3.40 / 3.4g (g) (1)
OR
0.025 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 working	2
 
(ii)	No, as copper carbonate is in excess	1
Reject no, as molar mass is only to one decimal place
 
(d)	Filter to remove excess copper carbonate	1
 
(e)	(i)	249.6	1
 
(ii)	Expected yield = 0.025 × 249.6 (1)
= 6.24g
	% yield = (100 × 3.98/6.24 )= 63.8/63.78% (1)	2
[9]

55.	(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 electrons
are free to move and carry charge / current (1)	3
Reject incorrect use of the terms atom or molecule for ion.
Reject incorrect descriptions of delocalised electrons.
 
(b)	(i)	Mg^2+ 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)	1
Reject 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 configuration	1
Reject same number of electrons in outer orbit
 
(e)	(i)	1.20 × 10^–9 mol of Mg per dm^3 (1)
(1.20 × 10^–9 × 24.3 × 10^–3) =
2.92 × 10^–11 / 29.2 × 10^–12 (g) (1)
max 1 for more/less than 3 significant figures eg 2.916	2
 
(ii)	Hydrogen because it has the least number of electrons per atom	1
[12]

St John's RC Comprehensive School