Four elements P, Q, R and S have atomic numbers 12, 13, 14 and 15 respectively. Answer the following questions giving reasons :
(i) What is the valency of element Q ? (ii) Classify these elements as metals and non-metals.
(iii) Which of the elements will form the most basic oxide ?

Explanation

The electronic configuration of the element are as follows :
p (Z = 12), 2, 8, 2 Q (Z = 13) 2, 8, 3
R (Z = 14) , 2, 8, 4 S (Z = 15) 2, 8, 5
(i) The valency of the element Q is 3 since it has three valence electrons.
(ii) The elements P and Q are metals while the elements R and S are non-metals.
(iii) The element P will form the most basic oxide of formula PO.