Chemistry · PYQ NEET UG 2016(1)

The electronic configurations of Eu (atomic no. 63), Gd (atomic no. 64) and Tb (atomic no. 65) are ______ respectively.

1. \( [\text{Xe}] 4f^6 5d^1 6s^2 \), \( [\text{Xe}] 4f^7 5d^1 6s^2 \) and \( [\text{Xe}] 4f^8 5d^1 6s^2 \)
2. \( [\text{Xe}] 4f^6 5d^1 6s^2 \), \( [\text{Xe}] 4f^7 5d^1 6s^2 \) and \( [\text{Xe}] 4f^9 6s^2 \)
3. \( [\text{Xe}] 4f^7 6s^2 \), \( [\text{Xe}] 4f^8 6s^2 \) and \( [\text{Xe}] 4f^8 5d^1 6s^2 \)
4. \( [\text{Xe}] 4f^7 6s^2 \), \( [\text{Xe}] 4f^7 5d^1 6s^2 \) and \( [\text{Xe}] 4f^9 6s^2 \)