Which element will form only covalent compounds?

Question

The following table shows the position of six elements A, B, C, D, E and F in the Periodic Table.

Groups → Periods ↴	1	2	3 to 12	13	14	15	16	17	18
2	A					B			C
3	D				E				F

Using the above table answer the following questions: 

(i) Which element will form only covalent compounds?

 (ii) Which element is a metal with valency 2? 

(iii) Which element is a non-metal with valency 3? 

(iv) Write a common name for the family of elements C and F. 

(v) Out of D and E, which one has a bigger atomic radius and why?

Answer 1

(i) E 

(ii) D 

(iii) B 

(iv) The noble gases. 

(v) D has bigger atomic radius. The atomic radius decreases in moving from left to right along a period. This is due to an increase in nuclear charge which tends to pull the electrons closer to the nucleus and reduces the size of the atom.