Question

Total number of electron in phosphorus which have zero value of at least one quantum number.

Answer 1

The electronic configuration of phosphorous is
${}_{15}P\to 1s^{2}2s^{2}2p^{6}3s^{2}3p^{3}for{}^{\prime }{s}^{\prime }l=0,m=0$
For ${}^{\prime }{p}^{\prime }l=1,m=-1,+1,0$
So total number of electrons in $s-$ orbital is $6$.
Again 2 electrons of $2p$ subshell has $m_l=0$ value and one electron of $3p$ subshell has $m_l=0$
So, total number of electrons having atleast one quantum number is$=6+2+1=9$