The electronic configuration of gadolinium (atomic number 64) is:

Options

A. `[Xe]4f^(8)5d^(9)6s^(2)`
B. `[Xe]4f^(7)5d^(1)6s^(2)`
C. `[Xe]4f^(3)5d^(5)6s^(2)`
D. `[Xe]4f^(6)5d^(2)6s^(2)`

Answer

B

Explanation

Atomic no. of Xe is 54. So gadolinium has 10 more electrons than Xe.
`64=[Xe]4f^(7)5d^(1)6s^(2)`
Because of half filled orbital `[Xe]4f^(7)5d^(1)6s^(2)` is more stable than `[Xe]4f^(6)5d^(2)6s^(2)`.