Question

what are the electrovalencies of iron?? ​

Answer 1

Answer:

Iron can lose two electrons from the outermost 4s subshell to show a valency of two. Then it can lose another electron from the 3d subshell (penultimate) to show a valency of three.

When it shows the valency of two the electron configuration is 1s^2 2s^2 2p^6 3s^2 3p^6 3d^6.

When it shows the valency of three the electron configuration is 1s^2 2s^22p6 3s^2 3p^6 3d^5

And the +3 valence state is more stable than the +2 valence state because the d-orbital contains 5 electrons (half-filled).

As fully filled and exactly half-filled orbitals are more stable than the orbitals having different no of electrons, i.e. less than half filled and more than half filled but not fully filled.