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

Options

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

Answer

D

Explanation

Factual.