Question

Why element in 16th group has greater valency than elements in 17th group

Answer 1

because 16th group element is naturally occurring gases like oxygen tellurium etc.

Answer 2

heya good morning.......
#dear.........
bcoz of when we down the group than atomic number and size is increased and increase the Valence Shells of atom.and the electronegativity of the is greater than that group.
I hope it's helpful to you..........