Question

Why elements show variable valency?

Answer 1

Sometimes, the 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.

The reason behind Why they lose this extra electron is purely a matter of the specific element, what electron shell they are losing/gaining electrons in, and their relative energies to the previous/ next electron shell. Also their ability to share electrons between these shells

Transition metals show variable valency and these elements have d-orbital as penultimate orbital and the outermost orbital is the s-orbital.





An atom of an element can sometimes lose more electrons than are present in its valence shell, i.e. Loss from penultimate shell, and hence exhibit more than one or variable valency.