Question

Identify the ion having 4f\(^6\) electronic configuration.}\\[6pt]

• A. Gd\(^{3+}\)
• B. Sm\(^{3+}\)
• C. Sm\(^{2+}\)
• D. Tb\(^{3+}\)

Answer 1

The Correct Option is C

The electronic configuration of Gd (Gadolinium) is [Xe] 4f⁷ 5d¹ 6s². When Gd loses 3 electrons (one from the 6s orbital and two from the 5d orbital), it becomes Gd³⁺ with the electronic configuration [Xe] 4f⁷. This configuration does *not* match 4f⁶.

The electronic configuration of Sm (Samarium) is [Xe] 4f⁶ 6s². When Sm loses 2 electrons from the 6s orbital, it becomes Sm²⁺ with the configuration [Xe] 4f⁶. This matches the given 4f⁶ configuration.

The configuration of Sm³⁺ is [Xe] 4f⁵, and that of Tb³⁺ (Terbium) is [Xe] 4f⁸. Neither of these matches the required configuration.

Therefore, the ion with a 4f⁶ configuration is Sm²⁺.