Question
Thu February 28, 2008 By:

 

why are f-block elements called inner- transition elements?

f-block

Expert Reply
Thu February 28, 2008
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.                                                                   

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