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Lanthanoid ions with 4f 7 configuration are : (A) Eu 2+ (B) Gd 3+ (C) Eu 3+ (D) Tb 3+ (E) Sm 2+ Choose the correct answer from the options given below :

1. (A) and (B) only
2. (A) and (D) only
3. (B) and (E) only
4. (B) and (C) only

Correct answer: (A) and (B) only

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