GKFix MCQ Question

What is the primary difference in the electronic configurations of Tb³⁺ and Tb⁴⁺ ions?

• A. Tb³⁺ has a 4f⁸ configuration, while Tb⁴⁺ has a 4f⁷ configuration
• B. Tb³⁺ has a 4f⁷ configuration, while Tb⁴⁺ has a 4f⁸ configuration
• C. Tb³⁺ has a 4f⁹ configuration, while Tb⁴⁺ has a 4f⁸ configuration
• D. Tb³⁺ has a 4f⁸ configuration, while Tb⁴⁺ has a 5d¹ configuration