Question

Outer electronic configurations of $K,Cu,$ and $Cr$ are respectively :

• A. $4s^1,3d^{10},3d^5$
• B. $4s^2,3d^{10},3d^4$
• C. $4s^1,3d^9,3d^4$
• D. $4s^2,3d^9,3d^4$

Answer 1

The correct option is A $4s^1,3d^{10},3d^5$

The electronic configurations of the options are as follows:-

$K$ - $\left[Ar\right]4s^1$

$Cu$ - $\left[Ar\right]4s^{1}3d^{10}$

$Cr$ -$\left[Ar\right]4s^{1}3d^5$

Hence option A is the right answer.