Last saved by: jennifers

1.	(i)	2Mg + O_2 → 2MgO 
ALLOW multiples. Correct species must be seen
IGNORE state symbols
1
 
(ii)	Fizzes OR bubbles OR gas produced OR effervescing 
DO NOT ALLOW ‘carbon dioxide gas produced’
DO NOT ALLOW ‘hydrogen produced’ without ‘gas’
	Mg dissolves OR Mg disappears OR a solution is formed 
ALLOW ‘it for Mg’
IGNORE Mg reacts
IGNORE temperature change
IGNORE steam produced
2
 
(iii)	Quicker OR more vigorous OR gets hotter
MUST be a comparison of a reaction observation, not just ‘more reactive’
ALLOW any comparison of greater rate including more bubbles etc.
DO NOT ALLOW more gas produced
1
[4]

2.	(i)	Answer is inclusive of 9 − 14 inclusive 	1
(ii)	Ca(s):	1s^22s^22p^63s^23p^64s^2 
Ca(OH)_2(aq):	1s^22s^22p^63s^23p^6 	2
[3]

3.	(i)	loss (of electrons) 	1
(ii)	Ba 
0 → (+)2  (accept 2+)	2
[3]

4.	(i)	effervescence/bubbles 
Ra disappears/dissolves 	2
(ii)	8-14 	1
[3]

5.	barium atoms are larger 
barium atoms have more shielding 
this outweighs the increase in nuclear charge 
barium electrons are lost more easily
/less energy required
/ionisation energy decreases 
[4]

6.	(i)	Ca(OH)_2 
IGNORE charges, even if wrong
1
 
(ii)	Ca(NO_3)_2 
IGNORE charges, even if wrong
1
[2]

7.	(i)	hydrogen / H_2 	1
(ii)	Sr + 2H_2O → Sr(OH)_2 + H_2 	1
(iii)	different numbers of moles/atoms/ different A_r values
so different number of moles of H_2 /more moles of Ca
(i.e. an attempt to quantify difference)	2
(iv)	8 – 14 	1
[5]

8) reactivity increases (down the group) 
	atomic radii increase OR
there are more shells 
	there is more shielding OR more screening 
	the nuclear attraction decreases OR
Increased shielding and distance outweigh the
increased nuclear charge 
	easier to remove (outer) electrons OR
ionisation energy decreases 
USE annotations with ticks, crosses, ecf, etc for
this part.
DO NOT ALLOW more orbitals OR more sub-shells
‘More’ is essential
ALLOW ‘more electron repulsion from inner shells’
ALLOW ‘nuclear pull’
IGNORE any reference to ‘effective nuclear charge’
ALLOW easier to form positive ion