Identify the incorrect statement among the following -[AIEEE-07]a)d-block elements show irregular and erratic chemical properties among themselvesb)La and Lu have partially filled d-orbitals and no other partially filled orbitalsc)The chemistry of various lanthanoids is very similard)4f and 5f-orbitals are equally shieldedCorrect answer is option 'D'. Can you explain this answer?

Question

Answer

The correct answer is option D
4f and 5f belongs to different energy levels, hence the shielding effect on them is not the same. Shielding of 4f is more than 5f.

Answer

The reason is lanthanoid contraction. so the size is almost same and hence there are more electrons in almost the same radius of sphere. this results is higher  electron strength in previous shell electrons and hence the shielding is different

Answer

Incorrect statement: 4f and 5f-orbitals are equally shielded.

Explanation:
- The statement is incorrect because 4f and 5f-orbitals are not equally shielded.
- Shielding refers to the partial blocking of the attractive force between the nucleus and the valence electrons by inner-shell electrons.
- In the case of 4f orbitals, they are shielded by the 5s, 5p, and 5d orbitals, which are closer to the nucleus. Therefore, the shielding effect is relatively less for the 4f orbitals.
- On the other hand, in the case of 5f orbitals, they are shielded by the 6s, 6p, and 6d orbitals, which are farther from the nucleus. Therefore, the shielding effect is relatively more for the 5f orbitals.
- Due to this difference in shielding, the chemical properties of the 4f and 5f elements differ significantly.

Other statements:
a) d-block elements show irregular and erratic chemical properties among themselves
- This statement is correct. The d-block elements exhibit irregular and erratic chemical properties due to their variable oxidation states, complex formation, and similarities in their atomic and ionic radii.

b) La and Lu have partially filled d-orbitals and no other partially filled orbitals
- This statement is correct. La and Lu belong to the f-block of the periodic table and are part of the lanthanide series. Both elements have partially filled d-orbitals, with La having a partially filled 5d orbital and Lu having a partially filled 4f orbital.

c) The chemistry of various lanthanoids is very similar
- This statement is correct. The chemistry of the lanthanoids, also known as the rare earth elements, is very similar due to the presence of similar electronic configurations and similar properties arising from the filling of the 4f orbitals.

In conclusion, the incorrect statement among the given options is D, which states that 4f and 5f-orbitals are equally shielded.

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