How to find valency of zinc?

You take a look at its .
Zinc is located in period 4, group 12 of the and has an equal to 30.
This means that neutral zinc atom has a total of 30 electrons surrounding its nucleus. To see how many of these electrons are , write the of a neutral zinc atom.
##”Zn”: 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10##
or, if you use the
##”Zn”: [“Ar”] 4s^2 3d^10##
Notice that the outermost shell, which for zinc is the fourth shell, ##”n=4″##, has two electrons.
This means that zinc can lose the two electrons located in the 4s-orbital to be become the ##Zn^(2+)## cation.
##”Zn”^(2+): [“Ar”] 3d^10##
Notice that the 3d-orbital is completely filled, which means that these electrons behave like core electrons and cannot be considered .
Therefore, zinc has only 2 , both located in the 4s-orbital.