Question

What is variable valency? Give example of a metal and a non metal each of variable valency.

Answer 1

Some elements have more than one valency. These elements are said to have variable valancy.

Metal which have variable valency is iron-3,2

Nonmetal which have variable valency is sulphur-2,4,6

Answer 2

an element with multiple valencies or oxidation states.
eg:
metal- Fe-iron -- oxidation states- +2,+3
non metal- S-sulphur --oxidation states- -2,-4,-6