An element with Z = 9 of modern periodic table belongs to same group as that of the element with Z = 

Hints to predict the position of element in the Modern periodic table :1)Elements from Z = 58-71……Lanthanoids…..4f series….6th period……3rd(IIIB) group;2)Elements from Z = 90-103……Actinoids…..5f series….7th period……3rd(IIIB) group;3)Elements from Z = 104-118………..Last two digits gives group number….. 7th period;4)Elements from Z = 31-57….subtract 18 to get preceding element;5)Elements from Z = 72-89….subtract 32 to get preceding element;6)Elements from Z = 104-120….subtract 32 to get preceding element ;For Z=104-120….simplest Hint7)Elements from Z = 104-120….subtract 82 to get a lower member(Z<30) belonging to same group;Hints 4, 5 and 6 can be used repeatedly until an element belonging to same group with Z < 30 is obtained;Elements with Z < 30 with their group, period and block can be known from Electronic configuration;Ex : Z=117, 85, 53, 35, 17, 9….belong to 17th(VIIA) group;(117-32)=85; (85-32)=53; (53-18)=35; (35-18)=17;Z = 17…….Cl…..3s23p5….…n=3….3rd period……p-block….valence electrons(7)….17th group;Z = 35…….Br….4s24p5…….n=4….4th period……p-block….valence electrons(7)….17th group;Z = 53……..I……5s25p5…….n=5….5th period……p-block….valence electrons(7)….17th group;Z = 85…….At…..6s26p5…….n=6….6th period……p-block….valence electrons(7)….17th group;Z = 117……Ts….7s27p5….…n=7….7th period……p-block….valence electrons(7)….17th group;