Question

State the variable valency of the metal iron.

Answer 1

Variable valency

When elements have more than one valency it is called variable valency.

The atomic number of iron (Fe) is 26. Its electronic configuration is [2, 8, 14, 2].

Here it has 2 electrons in its outermost shell and hence its valency is +2.

But here its penultimate shell is not stable and 1 more electron jumps to the outermost shell, to achieve stability, increasing the valence electron and the new electronic configuration will be [2, 8, 13, 3]. Since there are 3 electrons in the valence shell, it has valency +3.