Four elements A, B, C and D have atomic numbers 12, 13, 14 and 15 respectively. Answer the following questions giving reasons : (i) What is the number of valence electrons and valency of D? (ii) Which of them will have largest atomic radii ? (iii) Which of these elements will form the most basic oxide ?

Four elements A, B, C and D have atomic numbers 12, 13, 14 and 15 resp

1.	Four elements A, B, C and D have atomic numbers 12, 13, 14 and 15 respectively. Answer the following questions giving reasons : (i) What is the number of valence electrons and valency of D? (ii) Which of them will have largest atomic radii ? (iii) Which of these elements will form the most basic oxide ?
Answer» Solution :(i) VALENCE electrons in .D. = 5 and VALENCY of .D. = 3. (ii) .A. will have largest atomic RADII because atomic radius decreases across a period from left to right. (iii) .A. will form the most basic OXIDE as it is most metallic.