group no. valency has no relation in
a- 1st group
b-2nd group
c-14th group
d-0 group
Group number and valency has no relation in group 0 (or Group 18) since the elements in group 0 are noble gases. They are inert and thus do not form compounds easily. However certain noble gases do form compounds under extreme conditions but in those cases the valency of the noble gas cannot be predicted from its group number. For example Xe forms compounds like XeF2 , XeF4 etc in which Xe has valency 2 and 4 respectively and these valencies have no relation with the group number, i.e. 18 .