Aarti Gupta
Magnetic quantum number(ml ) is one of the four quantum numbers.It refers to the different orientations electron cloud in a particular sub-shell.These different orientations are called the orbitals. The number of values allowed to ml depends on the values of l which is azimuthal quantum number which gives the sub-shell.The possible values of ml is given as-
ml = +l through 0 to -l.
For ex- if value of l = O ,value of ml = O.Thus for s sub-shell there will be only 1 orbital.
For l = 1, ml will have 3 values , +1,O and -1.Thus p-sub-shell has three orbitals.
For l = 2 ,ml will have 5 values, +2,+1,0, -1, -2.Thus d sub-shell has five orbitals.
This is how you can calculate the values of magnetic quantum number.