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Q.
Number of electrons having $l+m$ value equal to zero in ${ }_{26} Fe$ may be
Structure of Atom
Solution:
${ }_{26} Fe -1 s ^{2}, 2 s ^{2} 2 p ^{6}, 3 s ^{2} 3 p ^{6}, 3 d ^{6}, 4 s ^{2}$
$l+ m=0 \Rightarrow l =0, m=0\,\,\, i.e. s$-subshell
$l=1, m=-1$ i.e. one orbital of $p$ .
$l =2, m=-2$ i.e. one of $d$ -orbitals
Hence there are $13$ or $14$ electrons as in $d$-orbital there may be one or two electrons having $m=-2$.