Na, Mg, and Al are the elements of the 3rd period of the Modern Periodic Table having group number 1, 2, and 13 respectively. Which one of these elements has the a) highest valency, (b) largest atomic radius, and (c) maximum chemical reactivity?

Na, Mg, and Al are the elements of the 3rd period of the Modern Period

1.	Na, Mg, and Al are the elements of the 3rd period of the Modern Periodic Table having group number 1, 2, and 13 respectively. Which one of these elements has the a) highest valency, (b) largest atomic radius, and (c) maximum chemical reactivity?
Answer» Solution :a) ELEMENTS having group number 1, 2, and 13 have a valency of 1, 2, and 3 RESPECTIVELY. So, AL has the highest valency. b] Atomic radius decreases along a period. So, Na has the largest atomic radius. c] Na has the maximum chemical reactivity since chemical reactivity decreases along a period.