http://www.xtremepapers.com/papers/CIE/Cambridge%20International%20A%20and%20AS%20Level/Chemistry%20(9701)/9701_s10_qp_11.pdf
qs 8,17,16,24,38,31
[8] Strontium (atomic weight - 88)
ONE mole of group 2 element needs ONE mole of chlorine molecule to completely react.
Number of moles of group 2 element (in this case, Strontium)= (2.92)/(88) = 0.033
Number of moles of chlorine = (5.287 - 2.920)/(35.5 X 2) = 0.033
[16] Silicon, Phosphorus, Sulfur
Regarding ionization energy, Phosphorus is an exception as it disturbs the increasing trend towards the right of the periodic table. It satisfies the other condition of lowest melting point.
[17] Second ionization energy
Ionization energy decreases as we go down the group 2 elements as removing outer electron becomes easier because reactivity increases as we descend down the periodic table for group 2.
[24] Propan-2-ol
NaBH
4 reduces propanone.
REMEMBER THIS : Secondary alcohol on oxidation gives a ketone, so in return while on reduction, ketone gives a secondary alcohol.
[31] 1 and 2
1 is diamond and
2 is graphite. These show giant molecular structure while
3 forms ionic lattice.
[38] 2 and 3
Numbering of a hydrocarbon chain starts from only one side and cannot start from both sides simultaneously. This is obeyed by
2 and
3.
