Question

how to find valency?

Answer 1

first write the electronic configuration of element then check the electrons in last shell .the no. of electrons in last shell will be it's valency only if it is till 4 .
after having more than 4 electro in valence shell it will be substracted from 8
ex. N- electronic configuration is 2,5
then valency = 8-5= 3

Answer 2

Hey there!!!
VALENCY
1). First and easiest way is simplify to consult the periodic table.The elements are sorted into groups and the elements in the groups 1 to 8 respectively have the same valency as others in their group.
for example all the elements in group 8 have 8 electrons.
2). the second method is to look at the total number of electrons and then calculate the valency if you don't know remember to look at the atomic number-(the number of electrons is always equal to the number of protons). The valency of an atom is equal to the number of electrons in the outer shell if that number is 4 or less.
otherwise the valency is equal to 8 minus the number of electrons in the outer shell.

hope it helps...