Which lanthanoid from following may exhibit +4 oxidation state with f ⁰ configuration?

Step-by-step solution

Lanthanoid electronic configurations generally follow [ Xe ] 4f^ n 5d⁰⁻¹ 6s^2 , with +3 being the most common oxidation state. Some lanthanoids show +2 or +4 oxidation states when stable f^0 , f^7 , or f¹⁴ configurations can be achieved. Cerium's ground state is [ Xe ] 4f^1 5d^1 6s^2 . Losing four electrons gives Ce ⁴⁺ with configuration [ Xe ] 4f^0 , a stable noble gas configuration explaining its known +4 oxidation state. In contrast: Europium yields [ Xe ] 4f^5 Terbium yields [ Xe ] 4f^7 Lutetium yields [ Xe ] 4