The mercury (Hg) has 80 electrons. The electrons are distributed in the s, p, d and f orbitals. The electronic configuration of Hg can be shown as-[tex]1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{6}4d^{10}5s^{2}5p^{6}4f^{14}5d^{10}6s^{2}[/tex]. We can see that there are two filled d-orbitals 3d and 4d. There is only one filled f orbital which is 4f. The electron cloud of the s, p, d and f are different due to their different screening and penetration effect towards the nucleus. The electron cloud of f-orbital is most diffuse than the other three. The outermost electrons of mercury is [tex]6s^{2}[/tex], which is its valence electrons i.e. (+2).
