Azimuthal quantum number (l): it desiibes the shape of electron cloud and the number of sub- shells in a shell .

it can have values from 0 to (n-1)

`{:("value of l","subshell"),(0,s),(1,p),(2,d),(3,f):}` Number of obitals in a subsjhell = 2l +1

Orbital angular momentum `L=(h)/(2 pi)sqrt(l(l+1))`

`hsqrt(l(l+1))" " [h=(h)/(2pi)]` magb=netic quantum number (m) :

it desicribes the orientations of the orbitals .It can have values from -l to + l including zerop i.e total (2l+1) values . Each value corresponds to an ot=rbital s- subshell has one orbital ,p - subshell three orbitals `(P_(x),P_(y)andP_(z))` d- subshell five orbitals `(D_(yz),d_(yz),d_(zx), d_(x^(2)-y^(2)),d_(z^(2))` and f- subshelll has seven orbtials .

Spin quantum number (s) :

It desiibes the spin of the electron , it has values `+(1)/(2)` and `-(1)/(2)` Signifies clock wise spining and anticlock wise rotion of electron about its Own axis . Spin of the electron produes spin angluar momentum equal to

`S=sqrt(s(s+1))(h)/(2pi), "where" s= +(1)/(2)`

total of the an atom `=+(n)/(2) or -(n)/(2)`

WHere n is the number of unpaired electron s .

the magnetic moment of an atom

`mu_(s)=sqrt(n(n+2))B.M`

n- number of unpaired electron s

B.M (Bohr magenton)

the correct order of the magnetic moment is :

`[""_(25)Mn,""_(26)Cr,""_(26)Fe]`

A. `Fe^(3+)gt Cr^(3+)=Mn ^(4+)`

B. `Fe^(3+)gt Cr^(3+)gtMn ^(4+)`

C. `Fe^(3+)= Cr^(3+)gtMn ^(4+)`

D. `Fe^(3+)gt Mn^(4+)gtCr ^(3+)`