why iron (Fe) has two valencies?

1.	why iron (Fe) has two valencies?
Answer» When iron has +2 valency it has actually lost its 4s electrons but when it has a valency of +3 ,it has lost 4s electrons along with one electron from the paired electrons in 3d orbital , thereby leaving unpaired electrons in each of the five 3d orbitals , this is because partially filled d orbitals have extra stability .

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