An element with Z = 78  belongs to……block……group and ……period of modern periodic table

detailed solution

Correct option is D

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=110, 78, 46, 28….belong to 10th(VIII) group;(110-32)=78; (78-32)=46; (46-18)=28;(n-1)d1-10ns1-2 ;Note : Many elements of d-block have anomalous configuration. So only GEC of each group is highlighted;Z = 28…….Ni…  4s23d8…….n=4…..4th period…..d-block….…..10th group;Z = 46…….Pd………….….….n=5….5th period……d-block……...10th group;Z = 78…….Pt…………..………n=6….6th period……d-block…..…10th group;Z = 110…..Ds…………..……..n=7…..7th period……..d-block..……..10th group;