Question

Answer the following questions for Zn atom:
How many electrons have $n+l+m$=$4$?

Answer 1

electronic configuration of Zn is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{1}04s^2$

Case $1:n=4,l=0,m=0$ means $\left[4s\right]$ which have 2 electrons.

Case $2:n=3,l=1,m=0$ means $\left[3p\right]$ which have 6 electrons.

Case $3:n=2,l=1,m=1$ means $\left[2p\right]$ which have 6 electrons.

So total number of electron having $[n+l+m=4]$ is $2+6+6=14$