Ncert Exercises & Solutions

On the basis of lanLhanuid contraction, explain the following:

1. Nature of bonding in $L a_{2} O_{3} a n d L u_{2} O_{3}$

2. Trends in the stability of oxo salts of lanthanoids from La to Lu.

3. Stability of the complexes of lanthanoids.

4. Radii of 4d and 5d block elements.

5. Trends in acidic character of lanthanoid oxides.

NEETprep Answer: (i) As the size decreases covalent character increases. Therefore,

L a_{2} O_{3}

is more ionic and

L u_{2} O_{3}

is more covalent.

(ii) As the size decreases trom La to Lu, stability of oxo salis also dectvases.

(iii) Stability of complexes increases asthe size of lanthanoids decreases,

(iv) Radii ol 4d and 6d block oloments will be altiast sare

(v) Acidic character of oxides increases from La to Lu.