The electronic configurations of Eu (Atomic no. 63 ), Gd (Atomic...

The electronic configurations of Eu (Atomic no.

63

), Gd (Atomic no.

64

) and Tb (Atomic no.

65

) are:

Options

A $\left[Xe\right]4{f}^{7}6{s}^{2}, \left[Xe\right]4{f}^{8}6{s}^{2}and\left[Xe\right]4{f}^{8}5{d}^{1}6{s}^{2}$
B $\left[Xe\right]4{f}^{6}5{d}^{1}6{s}^{2}, \left[Xe\right]4{f}^{7}5{d}^{1}6{s}^{2}and\left[Xe\right]4{f}^{9}6{s}^{2}$
C $\left[Xe\right]4{f}^{6}5{d}^{1}6{s}^{2}, \left[Xe\right]4{f}^{7}5{d}^{1}6{s}^{2}and\left[Xe\right]4{f}^{8}5{d}^{1}6{s}^{2}$
D $\left[Xe\right]4{f}^{7}6{s}^{2}, \left[Xe\right]4{f}^{7}5{d}^{1}6{s}^{2}and\left[Xe\right]4{f}^{9}6{s}^{2}$

D. $\left[Xe\right]4{f}^{7}6{s}^{2}, \left[Xe\right]4{f}^{7}5{d}^{1}6{s}^{2}and\left[Xe\right]4{f}^{9}6{s}^{2}$

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

Eu - \left[Xe\right]4{f}^{7}, 6{s}^{2}

Gd - \left[Xe\right]4{f}^{7}, 5{d}^{1}, 6{s}^{2}

Tb - \left[Xe\right]4{f}^{9}, 6{s}^{2}