Question

X- $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^1$

Y- $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^1$

Which of the given electronic configuration is correct?

• A. X is correct
• B. Y is correct
• C. Both are correct
• D. Both are wrong

Answer 1

The correct option is B

Y is correct

When electrons are added to the subshells of the atoms, they are filled in the order from subshells of lower energy to the higher energy. $4s^1$ is at lower energy than $3d^1$. Therefore, Y is the correct electronic configuration since $4s^1$ will get filled first than $3d^1$.