Assign reason for each of the following statement:
(i) The largest number of oxidation states are exhibited by the elements in their row transition elements.
(ii) The atomic radii decrease in Size with the increasing atomic number in the lanthanoid series

Answer

(i) The maximum number of oxidation state are shown by that element in a transition in a transition series which has maximum number of unpaired electrons. This is so in the middle of the series.
(ii) Cause of lanthanoid contraction.