The electronic configuration of Eu (Atomic No. 63), Gd (Atomic No. 64) and Tb (Atomic No. 65) are:

Options

A. `[Xe]4f^(6)5d^(1)6x^(2)` and `[Xe]4f^(9)6s^(2)`
B. `[Xe]4f^(6)5d^(1)6s^(2), [Xe]4f^(7)5d^(1)6s^(2)` and `[Xe] 4f^(8)5d^(1)6s^(2)`
C. `[Xe] 4f^(7)6s^(2), [Xe]4f^(7)5d^(1)6s^(2)` and `[Xe]4f^(9)6s^(2)`
D. `[Xe] 4f^(7) 6s^(2), [Xe]4f^(8) 6s^(2)` and `[Xe]4f^(8)5d^(1)6S^(2)`

Answer

C

Explanation

Electronic configuration of
`._(63)Eu = [Xe]_(54) 4f^(7)6s^(2)` Electronic configurationof `._(64)Gd = [Xe]_(54) 4f^(7)5d^(1)6s^(2)`
Electronic configuration of `._(65)Tb= [Xe]_(54)4f^(9)6s^(2)`