Comment on the statement that elements of the first transition series possess many properties different from those of heavier transition elements.

Explanation

(i) Elements in first transition series are more stable in lower oxidation states while heavier transition elements are stable in higher oxidation states.
(ii) The elements of 5d series have higher ionization enthalpies than 3d and 4d series elements.
(iii) The 3d series elements donot form a complex with a co-ordination number 7 and 8.
(iv) Heavier transition elements always form a low spin complexes irrespective of strength of spin complexes irrespective of strength of ligands while elements of 3d series form low spin and high spin complex depending upon the strength of ligands.