Question

What are transition elements?
Explain formation of variable oxidation states by them.

Answer 1

the elements having last two cells in completely filled are called as transition elements there are various formation of oxides like CuO Fe2O3 and so more

Answer 2

TRANSITION ELEMENTS.

"an element whose atom has a partially filled d sub-shell, or which can give rise to cations with an incomplete d sub-shell"

REASON.

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.