Question

Write the electronic configuration of $S{r}^{2+}$ in absence of Aufbau Principle.

• A. $1s^2,2s^{2}2p^6,3s^{2}3p^{6}3d^{10},4s^{2}4p^{5}4d^1$
• B. $1s^2,2s^{2}2p^6,3s^{2}3p^{6}3d^{10},4s^{2}4p^{3}4d^3$
• C. $1s^2,2s^{2}2p^6,3s^{2}3p^{6}3d^{10},4s^{2}4p^6$
• D. None of these

Answer 1

Answer: (C)

$1s^2,2s^{2}2p^6,3s^{2}3p^{6}3d^{10},4s^{2}4p^6$

According to the Aufbau principle, electrons are filled in the increasing order of $(n+l)$ value.
In the absence of Aufbau principle it wont follow the order of increasing $(n+l)$ value for filling up of electrons
So the electronic configuration of $S{r}^{2+}$(36 electrons) would be $1s^2,2s^{2}2p^6,3s^{2}3p^{6}3d^{10},4s^{2}4p^6$.
Hence, option $C$ is correct.