F321 module 2 Practice 2:

1.	(a)		3
element	structure	bonding		
Mg	giant	metallic	 	
Si	giant	covalent	 	
S	simple	covalent	 	
1 mark for each correct row
 
(b)	Si has strong forces between atoms/
covalent bonds are broken 
P has weak forces between molecules/
intermolecular forces/van der Waals’ forces are broken 	2
 
(c)	From Na ® Al, no of delocalised electrons increases 
charge on positive ion increases/
ionic size decreases/
charge density increases 
attraction between + ions and electrons increases/
metallic bonding gets stronger 	2
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2.	(i)	2Na(s) + Cl2(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
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3.	(a)		2

1, 2 or 3 p orbitals are OK
 
(b)	d orbital 2 
p sub-shell 6 
3rd shell 18 	3
 
(i)	

(ii)		2
2s and 2p labels  Ignore any superscripted numbers.
8 electrons in correct levels with arrows correctly shown 
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4.	(i)	Energy change when each atom in 1 mole 
of gaseous atoms 
loses an electron  (to form 1 mole of gaseous 1+ ions).	3
(ii)	O2+(g) ® O3+(g) + e− 	2
1 mark for correct species; 1 mark for state symbols
No charge required on electron.
Ignore (g) on e
(iii)	Large difference between 6th and 7th IEs 	2
marking a different shell (closer to nucleus) 
allow ‘inner shells’/new shell/full shell/first shell
marking points independent.
not sub-shell or orbital
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5.	

Also accept Na with full shell as long as it contains ‘x’s
(as in example above)
Ignore any inner shells
correct dot and cross 
correct charges 
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6.	(i)	2Na + O2 ® Na2O2 	1
(ii)	Na2O2 + 2H2O ® H2O2 + 2NaOH 	1
correct covalent bonds shown 
(iii)	electron count (14) for rest of molecule correct 	2
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7.	(i)	(trigonal) pyramidal	1
(ii)	electron pairs repel/bonds repel
/electron pairs get as far apart as possible 
lone pairs repel more/forces ‘them’ closer 
4 electron pairs surround central atom or N	3
/diagram with 3 bonds and a lone pair 
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8.	Original solution contains ions/there are mobile ions 
Charge carriers removed as reaction takes place
/as solid forms/ as BaSO4 forms/as water forms 	2
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9.	general
NaCl: ionic/has ionic bonds 
Beware of contradictions for this mark, especially
reference to intermolecular forces.
Ignore ‘atoms’.	2
graphite: covalent/giant molecular/macromolecular 
Ignore van der Waals’, intermolecular, molecules
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conductivity
NaCl:		ions cannot move/
no free ions (or electrons) /
mobile ions only in solution or when molten 
graphite:	2
delocalised electrons/
free electrons (between layers)/
electrons conduct 
Ignore lone pair
melting point
both graphite and NaCl:
bonds are strong/
bonds difficult to break /	1
large amount of energy is needed to break bonds

solubility
NaCl:		Water is polar/water has a dipole/
ions interacts with water molecules 
Graphite:	no interaction with water/
no intermolecular forces with water/	2
graphite is non-polar 
QWC:	At least 2 complete sentences in which
the meaning is clear. 	1
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10.	(i)	

		protons	neutrons	electrons
	25Mg	12	13	12	
26Mg	12	14	12		2
(ii)	1s22s22p63s2
24 ´ 78.60/100 + 25 ´ 10.11/100 + 26 ´ 11.29/100	1
(iii)	= 24.33  (calc value: 24.3269. This scores one mark)
24.32 with no working, award 1 mark only.
24.3 with no working, no marks (Periodic Table value)	2
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