An element with Z = 51  belongs to …………block of modern periodic table

detailed solution

Correct option is B

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=115, 83, 51, 33, 15, 7….belong to 15th(VA) group;(115-32)=83; (83-32)=51; (51-18)=33; (33-18)=15;Z = 15………P….3s23p3…..n=3….3rd period……p-block….valence electrons(5)….15th group;Z = 33…….As….4s24p3…..n=4….4th period……p-block….valence electrons(5)….15th group;Z = 51…….Sb….5s25p3…..n=5….5th period……p-block….valence electrons(5)….15th group;Z = 83…….Bi…..6s26p3…..n=6….6th period……p-block….valence electrons(5)….15th group;Z = 115…..Mc….7s27p3…..n=7….7th period……p-block….valence electrons(5)….15th group;