compound has no valency BUT it is the element that has valency
when we write any any element with its valency then it is called ion.
e.g. Na, K, has ----- one valency we write Na+1 & K+1
Ca, Ba. Mg have ---- two valency each Ca+2 , Ba+2 ,,Mg+2
Al,has ---- three valencies----------- Al+3
these when come in contact with nonmetals accepts one,or two, or three electrons
to form a compound e.g. Na Cl , K Br .so Cl & Br also have one valency each
now when there is more than one elements in a species then the charge on
them is called valency e.g. CO3-2 . SO4-2 have two valency each
NOW I THINK YOUR QUESTION IS THAT HOW TO FIND THE CHARGE
ON THESE IONS [ CATION & ANIONS ]
e g. NH4 now it has +1 charge as--------------
NH3 + H+ ---------------> NH4+1
Please mark it brainiest answer because i give a full description which taken around 15 minutes of my life..................Please...................If i deserve.