On the basis of Lanthanoid contraction, explain the following: (i) Nature of bonding in La_(2)O_(3) and Cu_(2)O_(3) (ii) Trends in the stability of oxo salts of lanthanoids from La to Lu (iii) Stability of the complexes of lanthanoids. (iv) Radii of 4d and 5d-block elements. (v) Trends in acidic character of lanthanoid oxides.

On the basis of Lanthanoid contraction, explain the following: (i) Na

1.	On the basis of Lanthanoid contraction, explain the following: (i) Nature of bonding in La_(2)O_(3) and Cu_(2)O_(3) (ii) Trends in the stability of oxo salts of lanthanoids from La to Lu (iii) Stability of the complexes of lanthanoids. (iv) Radii of 4d and 5d-block elements. (v) Trends in acidic character of lanthanoid oxides.
Answer» Solution :(i) From La to Lu, the size of ion decreases.Hence, `La_(2)O_(3)` is ionic while `Lu_(2)O_(3)` is a covalent OXIDE. (ii) Due to decrease in size, the stability of oxo-salts of LANTHANOIDS decreases from La to Lu (iii) As size decreases, the stability of complexes INCREASES. (iv) The 4f-orbitals are filled before the 5d-series of the elements beings. Due to intervention of 4f-orbitals, the lanthanoid contraction takes place. As a result, radii of 4d ADN 5d block elements are nearly of same size. (v) Acidic character of oxides increases from La to Lu.