Number of electrons having l+ m value equal to zero in ₂₆Fe may be

(A) 13

(B) 14

(C) 7

(D) 12

(AB)

Sol.   ₂₆Fe – 1s², 2s² 2p⁶, 3s² 2p⁶, 3d⁶, 4s²

         + m = 0          P       = 0, m = 0      i.e.            s-subshell

                                         = 1, m = –1     i.e.            one orbital of p

                                         = 2, m = 2      i.e.            one of d-orbitals

        hence there are 13 and 14 electron as in d-orbital it may be one or two electron having m = –2.