increases and electron electron repulsions repulsion increases.
c. Lanthanoid Contraction: The steady decrease in the atomic and ionic radii of the transition metals as the atomic number increases. This is because of filling of 4f orbitals before the 5d orbitals. This contraction is size is quite regular. This is called lanthanoid contraction. It is because of lanthanoid contraction that the atomic radii of the second row of transition elements are almost similar to those of the third row of transition elements.
d. Ionisation enthalpy: There is slight and irregular variation in ionization energies of transition metals due to irregular variation of atomic size. The I. E. of 5d transition series is higher than 3d and 4d transition series because of Lanthanoid Contraction.
e. Oxidation state: Transition metals show variable oxidation states due to tendency of( n-1) d as well as ns electrons to take part in bond formation.
f. Magnetic properties: Most of transition metals are paramagnetic in nature due to presence of unpaired electrons. It increase s from Sc to Cr and then decreases because number of unpaired and then decrease because