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On the basis of Lnathanoidcontraction , explain the following : (i)Nature of bonding in La_(2)O_(3) and Lu_(2)O_(3) (ii) Trends in the stability of oxio salts of lanthanoidsfrom La to Lu. (iii) Stability of the complexes of lanthanoids . (iv) Radii of 4d and 5d block elements.(v) Trends in acidiccharacter of lanthanoidoxides. |
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Answer» SOLUTION :(i) As the size decreases from La to Lu,covalent character increases ( according to Fajan's rule). HENCE, `La_(2)O_(3)` is more ionicand `Lu_(2)O_(3)` is more covalent. (ii) As the size decreasesfrom La to Lu, STABILITY of oxo salts decreases. (iii) As the size of lanthanoid decreases, charge `//`sizeratio increases andhence the stabilityof the complecxes increases. (iv) Due to lanthanoidcontraction, RADII of 4d and 5d BLOCK elements are nearly equal. (v) As explained in (i), covalend character of oxidesincreases from La to Lu, therefore, their basic character decreases or acidiccharacter increases. |
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