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 Q ? (ii) Classify these elements as metals and non-metals. (iii) Which of these elements will form the most basic oxide?

Four elements P, Q, R and S have atomic numbers 12, 13, 14 and 15 resp

1.	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 Q ? (ii) Classify these elements as metals and non-metals. (iii) Which of these elements will form the most basic oxide?
Answer» <P> Solution :(i) Q has atomic number 13. Thus, it has electronic configuration 2, 8, 3. Therefore, its valency is 3. (ii) Elements P and Q have 2 and 3 electrons respectively in the valence shell. They will have a TENDENCY to lose electrons and are therefore metals. Elements R and S have 4 and 5 electrons respectively in their valence shell. They will have tendency to gain or share the electrons to complete the OCTET. Therefore, R and S are non-metals. (iii) P will form the most BASIC oxide. Only the metals form basic oxide and P is more metallic than Q.