Solve this:
Study the following table in which positions of six elements A. B, C. D, E and F are shown as they are in the modern periodic table : On the basis is of the above table, answer the following questions :

(i) Name the element which forms only covalent compounds.
(ii) Name the element which is a metal with valency three.
(iii) Name the element which is a non-metal with valency three.
(iv) Out of D and E, which is bigger in size and why ?
(v) Write the common name for the family to which the elements C and F belong.