Why transition elements form a large number of complexes?

Account of the following. (i) The enthalpy of atomisation is lowest for Zn in 3d -series of the transition elements. (ii) Identify the metal in MO_(3)F and justify your answer. (iii) Transition metals form a large number of complexes. (iv) d^(1) configuration is very unstable in ions.

Define transition element.

Transition elements belong to

Explain the following : (i) The paramagnetic character in 3d-transition series increases upto Cr and then decreases. (ii) Transition metals are very good catalyst. (iii) Transition metals form a large number of interstitial compounds.