1. In terms of structure and bonding, explain the following observations: (a)The melting point of aluminium is higher than that of sodium. (1mark) (b)Melting point

1. In terms of structure and bonding, explain the following observations:
(a)The melting point of aluminium is higher than that of sodium. (1½mark)
(b)Melting point of chlorine is lower than that of sulphur(1½ mark)

2. Given that the atomic number of Y is 13 and that of Z is 9:
(a)Write the electronic arrangement of Y and Z; (1 mark)
(b)Draw the dot (.) and cross(x) diagram for the compound formed by Y and Z. (1 mark)

3. The atomic number of sulphur is 16. Write the electron arrangement of sulphur in the following:
(a)H2S (1 mark)
(b)SO32- (1 mark)

4. The atomic numbers of some elements P, Q, R and S are 6, 8, 12 and 17 respectively.
(a) Draw the dot (•) and cross (X) diagrams for the compounds formed when:
(i) R and Q react (1 mark)
(ii) P and S react. (1 mark)
(b) Explain why the melting point of the compound formed by P and S is lower than that formed by R and Q. (1 mark)