question_answer 47)

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

Answer:

The given statement is correct and is verified by the following examples: (i) Atomic radii of the heavier transition elements (4d and 5d series) are larger than those of the corresponding elements of the first transition series though those of 4d and 5d series are very close to each other. (ii)Melting and boiling points of heavier transition elements are greater than those of the first transition series due to stronger intermetallic bonding. (iii)Enthalpies of atomisation of 4d and 5d series are higher than the corresponding elements of the first series. (v) Ionization enthalpies of Sd series are higher than the corresponding elements of 3d and 4d series. The reasons for these variations is the increase in nuclear charge and size of the elements down the group which influence the properties.