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

Answer

B

Explanation

`[Xe]4f^(7) 6s^2 , [Xe]4f^(7) 5d^(1) 6s^2` and `[Xe] 4f^(9) 6s^2`