Question

Number of electrons having $l+m$ value equal to zero in ${}_{26}Fe$ may be:

• A. 13
• B. 14
• C. 7
• D. 12

Answer 1

Answer: (A), (B)

The correct options are
A 13
B 14

E.C. of $Fe$ $=1s^2,2s^2,2p^6,3s^2,3p^6,3d^6,4s^2$

$l+m=0$

$l=0,m=0$, i.e. s-subshell. So, total electrons in s $=2+2+2+2=8$.

$l=1,m=-1$, i.e. 2 orbitals of p. So total electrons in p having this condition$=2+2=4$.

$l=2,m=-2$, i.e. one of d-orbitals. So, there can be $1$ or $2$ electrons in $m$$=$$2$ for d-subshell since there are total $6$ electrons in $3d$ subshell.

Hence, there are $13$ or $14$ electron as in d-orbital it may be one or two electrons having $m=2$.