Question

Iron loses its outermost 2 electrons of 4s2 orbital. Hence it has +2 valency. Now the 3rd shell or M Shell rather more specifically the 3d6 orbital becomes exposed. Fe will once again try to fill up this shell to attain the electronic configuration of its nearest noble gas Kr. To do so, it will try to fill up its 3rd shell or M Shell. The M Shell can contain maximum 8 electrons but in iron it contains : 3s2 3p6 3d6. That is, 2+6+6=14 electrons. Following the octet rule it would be 2,8,4 hence there are 8-4 electrons missing. Thus iron can either lose or gain 4 electrons but not 3 electrons. But then why does it have valency +3 and not +4/-4?

Answer 1