Why do some elements show variable valency?

Why do some elements show variable valency?

Sometimes, same element may exhibit one valency in one compound and another valency in other compound. This property is called as variable valency .

  • Some elements show variable valency because of the different electronic configurations.
  • An atom of an element can sometimes lose more electrons than are present in its valence shell i.e. loss from the penultimate shell and hence exhibit more than 1 or variable valency.