Gadolinium belongsd to 4f series. It's atomic number is 64. which of the following is the correct electronic configuration of gadolinium ?

Options

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

Answer

A

Explanation

Gadolinium belongs to 4f series and has atomic number 64. The correct electronic configuration of gadolinium is
`" "._(64)Gd=._(54)[Xe] 4f^(7) 5d^(1)6s^(2)`
It has extra stability due to half-filled 4f subshell.