Identify the ion having 4f\(^6\) electronic configuration.
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+.
Correct Answer:
Option 3: Sm2+
Explanation:
1. Gd3+ (Gadolinium(III) ion):
Gd: [Xe] 4f7 5d1 6s2
Gd3+: [Xe] 4f7
2. Sm3+ (Samarium(III) ion):
Sm: [Xe] 4f6 6s2
Sm3+: [Xe] 4f5
3. Sm2+ (Samarium(II) ion):
Sm: [Xe] 4f6 6s2
Sm2+: [Xe] 4f6
4. Tb3+ (Terbium(III) ion):
Tb: [Xe] 4f9 6s2
Tb3+: [Xe] 4f8
Therefore, Sm2+ has the 4f6 electronic configuration.
\( \text{M} \xrightarrow{\text{CH}_3\text{MgBr}} \text{N} + \text{CH}_4 \uparrow \xrightarrow{\text{H}^+} \text{CH}_3\text{COCH}_2\text{COCH}_3 \)