Question

Indicate the number of unpaired electrons in: Fe

Answer 1

Step 1: Writing the electronic configuration

atomic number of Fe- 26, The electronic configuration of Iron is: $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}4{\mathrm{s}}^{2}3{\mathrm{d}}^6$

Thus we can see that it has 6 valence electrons in its outermost shell

Step 2: Calculating the unpaired electrons

In Iron, the 3d-subshell has 6 electrons in it.

Now we know that these electrons will fill the orbitals according to Hund's rule of maximum multiplicity

That is the orbitals will first be filled singly and after all the orbitals are filled singly, then the pairing of the electrons will start.

For Iron, if we draw the 4s and 3d orbital:

Here we can see that in the 3d orbital, there are 4 unpaired electrons present.

Therefore, Iron has 4 unpaired electrons present in it.