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BONDING, STRUCTURE AND PERIODICITY TEST MS
1.	(i)		4 Na + O_2 → 2 Na_2O
	OR 2 Na + ½ O_2 → Na_2O 
ALLOW correct multiples including fractions
IGNORE state symbols
1
(ii)	(electrostatic) attraction between oppositely charged ions
1
(iii)	

	Na shown with either 8 or 0 electrons
AND
O shown with 8 electrons with 6 crosses and 2 dots (or
vice versa) 
Correct charges on both ions 
For 1st mark, if 8 electrons shown around cation then
‘extra’ electron(s) around anion must match symbol
chosen for electrons in cation
Shell circles not required
IGNORE inner shell electrons
ALLOW: 2[Na^+] 2[Na]^+ [Na^+]_2 (brackets not required)
DO NOT ALLOW [Na_2]^2+ / [Na_2]^+ / [2Na]^2+
DO NOT ALLOW: [Na_2]^2+ [Na_2]^+ [2Na]^2+ [Na]_2^+
2
[4]
 
2.	(i)	2Na(s) + Cl_2(g) → 2NaCl(s) 
1st mark for equation	2
2nd mark for state symbols
(ii)	Giant ionic (lattice) or 3D 
with alternating Na^+ and Cl^– 	2
[4]

3.	

	regular arrangement of labelled + ions with some attempt
to show electrons 
	scattering of labelled electrons between other species
OR
a statement anywhere of delocalised electrons (can be in
text below) 
	metallic bond as (electrostatic) attraction between the
electrons and the positive ions 
Lattice must have at least 2 rows of positive ions
If a metal ion is shown (e.g. Na^+), it must have the correct charge
ALLOW for labels: + ions, positive ions, cations
If ‘+’ is unlabelled in diagram, award the label for ‘+’ from a statement of ‘positive ions’ in text below
DO NOT ALLOW as label or text positive atom OR protons OR nuclei
ALLOW e^– OR e as label for electron
DO NOT ALLOW ‘–’ as label for electron
[3]

 4.	shared pair  of electrons 
i.e. ‘shared electrons’ is worth 1 mark. pair of electrons
for second mark
[2]
 
5.	H_2O:	all correct including lone pairs around O 
CO_2:		correct covalent bonds around carbon 
lone pairs added around oxygen atoms 
(must be ‘dot AND cross’ or electron source clearly shown
(different coloured for source is OK)
[3]

6.	(i)	dative covalent, bonded pair comes from same atom/	1
electron pair is donated from one atom/
both electrons are from the same atom 
(ii)	Ca(NO_3)_2 → CaO + 2NO_2 + ½O_2 
or double equation with 2/2/4/1	1
[2]

7.	(i)	Electron pairs in covalent bonds shown correctly using dots and
crosses in a molecule of the F_2O 
	Lone pairs correct on O and both F atoms 

Must be ‘dot-and-cross’
circles for outer shells NOT needed
IGNORE inner shells
Non-bonding electrons of O do not need to be shown as pairs
Non-bonding electrons of F do not need to be shown as pairs
2
(ii)	Predicted bond angle 104 – 105°. 
ALLOW 103 – 105° (103° is the actual bond angle)
	There are 2 bonded pairs and 2 lone pairs 
Lone pairs repel more than bonded pairs 
ALLOW responses equivalent to second marking point. e.g. There are 4 pairs of electrons and 2 of these are lone pairs
ALLOW ‘bonds’ for ‘bonded pairs’
DO NOT ALLOW ‘atoms repel’
DO NOT ALLOW electrons repel
ALLOW LP for ‘lone pair’
ALLOW BP for bonded pair
ALLOW LP repel more if bonded pairs have already been mentioned
3
[5]

8.	(i)	mark vertically:
	H_2O	NH_3
	2	3
	2	1	2
		
3D Diagram required or diagram with name
(ii)	labelled bond angle required
NH_3        pyramidal molecule shown 	107 ° (106-108°)
SO_2        non-linear molecule shown        110 – 130 ° 	4
[6]

9.	(i)	Attraction of electrons  in a bond  towards an atom	2
(ii)	CO_2 is symmetrical/H_2O is not symmetrical 
In CO_2, dipoles cancel/in H_2O, the dipoles don’t cancel 	2
[4]

10.	H_2O
H bonding from O of 1 molecule to H of another 
dipoles shown or described 	3
with lone pair of O involved in the bond 
CH_4
van der Waals’ forces from oscillating dipoles/ temporary
dipoles/ transient dipoles/ instantaneous dipoles 
leading to induced dipoles 
caused by uneven distribution of electrons 	3
[6]

11.	ice is less dense than water
hydrogen bonds hold H_2O molecules apart in ice /
hydrogen bonds cause an open lattice structure	2
[2]

12.	High boiling point or difficult to break linked to strong bonds in the right
context within Li or C 	1
Li	conducts by delocalised/free/mobile electrons  structure: giant metallic 	3
or ‘+ ions with a sea of electrons’ for giant mark
C	conducts by delocalised/free/mobile electrons  structure: giant covalent
with layers 	4
N	No mobile charge carriers/electrons/ions to conduct electricity 
simple molecular structure/made of N_2 molecules
low boiling point or easily broken due to	3
intermolecular forces/
van der Waals’ forces 
QWC:	At least 2 complete sentences in which the meaning is clear. 	1
[12]

13.	(i)	S (1)	1
(ii)	Al (1)	1
(iii)	B (1)	1
(iv)	Ca (1)	1
(v)	K (1)	1
(vi)	K (1)	1
[6]

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