Question

Gadolinium belongs to 4f series. Its atomic number is 64 . Which of the following is the correct electronic configuration of gadolinium ?
A. `[Xe]4f^(7) 5d^(1) 6s^(2)`
B. `[Xe]4f^(6)5d^(2) 6s^(2)`
C. `[Xe]4f^(8) 6s^(2)`
D. `[Xe]4f^(9)5s^(1)`

Answer 1

Correct Answer - a
`. _(64) Gd= [Xe]^(54) 4f^(7) 5d^(1) 6s^(2)` ( due to extra stability of half- filled 4f subshell)