Question

The position of 3 elements A, B and C in the Periodic Table is shown below: 

Giving reasons, explain the following: 

(a) Element A is a non-metal. 

(b) Atom of element C has larger size than A. 

(c) Element B has a valency of 1.

Answer 1

(a) A belongs to 7th group, has 7 valence electron, it can gain 1 electron to become stable. So it is a non-metal as it forms negative ion. 

(b) ‘C’ has 3 shells ‘A’ has 2 shells so C is bigger than A. 

(c) ‘B’ has one valence electron, it can loose this electron to become stable. So its valency is 1.