Give one example of each-a)Metal having valency 2
b)Non metal having valency 2.
c)Element with completely filled outermost shell.d)Element with three shells, having 4 electrons in the outermost shell

a. Beryllium is metal having valency 2.
b. Oxygen is non metal having the valency 2.
c. Helium and other members of group 18.
d. Silicon is the element having the 4 electrons in the outermost shell and it has 3 shells.