Get premium membership and access revision papers with marking schemes, video lessons and live classes.

Processing. Please wait.

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
(ii) P and S react.
(b) Explain why the melting point of the compound
formed by P and S is lower than that formed by R and
Q.