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Home Questions TAXN62R98E
Target Exam

CUET

Subject

Chemistry

Chapter

Inorganic: D and F Block Elements

Question:

The characteristic oxidation state of Lanthanoids is +3 but Ce shows +4 oxidation state becau.............

(A) it has variable ionization enthalpy
(B) it has a tendency to attain noble gas configuration
(C) it has a tendency to attain $f^0$ configuration
(D) it resembles $Pb^{4+}$

Choose the correct answer from the options given below:

Options:

(A), (B) and (C) only

(C) and (D) only

(A) and (C) only

(B) and (C) only

Correct Answer:

(B) and (C) only

Explanation:

The correct answer is Option (4) → (B) and (C) only

Lanthanoids generally show +3 oxidation state.
Cerium (Ce) shows +4 oxidation state because:

  • Ce⁴⁺ has an f⁰ configuration, which is particularly stable 
  • It also corresponds to attaining a noble gas–like configuration (similar to Xe core) 

Evaluate statements:

  • (A) Variable ionization enthalpy → not the main reason INCORRECT
  • (B) Tendency to attain noble gas configuration → CORRECT
  • (C) Tendency to attain f⁰ configuration → CORRECT
  • (D) Resembles Pb⁴⁺ → irrelevant  INCORRECT

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