Explanation:
Iron (Fe) is a d-block element. The d-block elements are also known as transition metals. The atomic number of Fe is 26.
Therefore, for an isolated iron atom which is not attached to any ligands, the electronic configuration will be as follows.
[tex]1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^6[/tex]
