the second shell ( n = ), three ( l = , , ) in third shell ( n = ) and so on. Each sub-shell is assigned an azimuthal quantum number ( l ). Sub-shells corresponding to different values of l are represented by the following symbols. Value for l : ............
notation for s p d f g h ............ sub-shell Table . shows the permissible values of ‘ l ’ for a given principal quantum number and the corresponding sub-shell notation. Magnetic orbital quantum number.
‘ m l ’ 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) l + values of m l are possible and these values are given by : m l = – l , – ( l – ), – ( l – )... , ... ( l – ), ( l – ), l Thus for l = , the only permitted value of m l = , [ ( )+ = , one s orbital].
For l = , m l can be – , and + [ ( )+ = , three p orbitals]. For l = , m l = – , – , , + and + , [ ( )+ = , five d orbitals]. It should be noted that the values of m l are derived from l and that the value of l are derived from n. Table .
Subshell Notations l Subshell notation 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f Each orbital in an atom, therefore, is defined by a set of values for n , l and m l . An orbital described by the quantum numbers n = , l = , m l = is an orbital in the p sub- shell of the second shell. The following chart gives the relation between the subshell and the number of orbitals associated with it. Value of l Subshell notation s