Question

explain briefly why the electronic configuration of lanthanides not known with certainty​

Answer 1

hey mate here is the answer

in the $\color{green}\boxed{attachment}$.

in other words ⤵
The electrons can easily jump from 4f to 5d or vice-versa. Further, irregularities in electronic configurations are also related to the stabilities of f0 f7 and f14 occupancy of f-orbitals. Hence, their electronic configurationsare not known with certainty.


thank u ❤