Question

What is the valency? How to find out using given compound?

Answer 1

combining capacity of an element is known as valency. ..when we write a formula of a compound then we intercross their valency and . Here Zn2O3- valency of zn =3 and valency of o =2

Answer 2

Valency is the combining capacity of an atom of a particular element.
In simple words, it tells that while bonding between the atoms of elements , how many electrons will be exchanged to make the atoms stable.

Now the given compound is Zn₂O₃.
Here, this shows that bonding has occurred between the atoms of Oxygen and Zinc to form a compound Zinc Oxide.

Always remember that the numbers at the subscript of the symbol of the element represent how many electrons that electron has gained or lost while the exchange to form the compound.

For example here, in Zinc Oxide ,
Zn has 2 this means that it Oxygen atom has lost it's two electrons and given it to Zinc atom while bonding. Similarly with oxygen atom.

This means that the valency of Oxygen = 2 
and the Valency of Zinc = 3.

Hope you understand the concept .........
If you feel any doubts you  can surely ask them

# Dhruvsh