Question

Identify the incorrect statement among the following.

• A. 4f-and 5f-orbitals are equally shielded.
• B. d-block elements show irregular and erratic chemical properties among themselves.
• C. La and Lu have partially filled d-orbitals and no other partially filled orbitals.
• D. The chemistry of various lanthanoids is very similar

Answer 1

Answer: (A)

The decrease in the torce of attraction exerted by the nucleus on the valency electrons due to the presence of electrons in the inner-shells is called shielding effect. A $4f$-orbital is nearer to the nucleus than $5f$-orbitals.
Hence, shielding of $4f$ is more than $5f$.