Question

Which of the following electronic configuration is not possible?

• A. $1s^2,2s^2$
• B. $3d^{10},4s^2,4p^2$
• C. $1s^2,2s^2,2p^6$
• D. $1s^2,2s^2,2p^2,3s^1$

Answer 1

Answer: (D)

$1s^2,2s^2,2p^2,3s^1$ configuration is not possible because electron cannot goes in $3s$ orbital without filling $2p$ subshell.