Question

A non metal with 3 electrons in the outermost shell

Answer 1

There is no such nonmetal with 3 electrons in the outermost shell. Some elements are there which has 3 electrons in the outermost shell, like

Aluminium(13)--> 2,8,3 (metal)

Boron(5)-->2,3(metalloid)

So, Boron will be more suitable.

Answer 2

aluminium and boron
is the answer