Explain the colour and para magnetic property of transition elements.

Explanation

Transition elements having unpaired electrons in d-orbitals are coloured. The colour is due to d-d transitions of electrons. Electrons are excited from lower set of d-orditals to higher set of dorbitals by absorbing energy from visible light and emits complementary colour which is the colour of the ion. Transition elements are ions having atleast one unpaired electron in d-orbitals are para magnetic. The extent of para magnetic property is expressed in terms of magnetic moment `(mu). mu = sqrt(n(n+2))` where n is number of unpaired electrons present in d-orbitals.