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CBSE - XII Science - Chemistry - The d-Block and f-Block Elements


Asked by 28th February 2008, 12:41 PM
Answered by Expert


why are f-block elements called inner- transition elements?Differentiate between lanthanoids and actinoids? Discuss the trend of ionic size and oxidation states in actinoids? (plz. Answer them, don’t tell me to refer

f-block elements called inner- transition elements as they have n-2 orbital incomplete. electronic configuration is 5f in complete and 7s filled.  There is a steady decrease in the atomic and ionic radii M3+as the atomic number increases. This contraction in size is quite regular which is called actinoid contraction.) Lanthanoids mainly exhibit +3 oxidation state. In addition, they show lower oxidation state of +2 and higher oxidation state of +4. Actinoids also exhibit +3 oxidation state. In addition, they show a wide range of higher oxidation states from +4 to +7. This is due to comparable energies of 5f, 6d and 7s orbitals in actinoids.                                                                   

Answered by Expert 20th December 2017, 4:08 PM

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