NCERT Exercise 4.10 - The d- and f-Block Elements
Question: The 5f electrons are more effectively shielded from nuclear charge. In other words the 5f electrons themselves provide poor shielding from element to element in the series.
Answer: **NCERT answer:** +3 is the common oxidation state of the lanthanoids In addition to +3, oxidation states +2 and +4 are also exhibited by some of the lanthanoids.
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