Principal quantum number ( n ): It identifies shell , determines sizes and energy of orbitals
Azimuthal quantum number ( l ): Azimuthal quantum number . ‘ l ’ is also known as orbital angular momentum or subsidiary quantum number . l . It identifies sub-shell , determines the shape of orbitals , energy of orbitals in multi-electron atoms along with principal quantum number and orbital angular
momentum , i . e ., The number of orbitals in a subshell = 2l + 1 . For a given value of n , it can have n values ranging from 0 to n-1 . Total number of subshells in a particular shell is equal to the value of n .
Subshell s p d f g notation Value of ‘ l ’ 0 1 2 3 4 Number of 1 3 5 7 9 orbitals
Magnetic quantum number or Magnetic orbital quantum number ( ml ): It gives information about the spatial orientation of the orbital with respect to standard set of co-ordinate axis . For any sub-shell ( defined by ‘ l ’ value ) 2l + 1 values of ml are possible . For each value of l , ml = – l , – ( l – 1 ), – ( l – 2 )... 0,1 ... ( l – 2 ), ( l – 1 ), l
Electron spin quantum number ( ms ): It refers to orientation of the spin of the electron . It can have two values + 1 / 2 and -1 / 2 . + 1 / 2 identifies the clockwise spin and -1 / 2 identifies the anti- clockwise spin .