Select the Lanthanoids which show +2 oxidation state?

(A) Yb
(B) Ce
(C) Eu
(D) Ho

Choose the correct answer from the options given below:

(A) and (C) only

The correct answer is Option (2) → (A) and (C) only

The +2 oxidation state is observed in some lanthanoids with half-filled or fully filled f-orbitals:

• Yb (Ytterbium) → [Xe]4f¹⁴6s² → +2 stable ✅
• Eu (Europium) → [Xe]4f⁷6s² → +2 stable ✅
• Ce (Cerium) → mostly +3 (rarely +4), +2 not common ❌
• Ho (Holmium) → mostly +3, +2 very rare ❌

✅ Correct answer: (A) and (C) only