Answer
Procedure
The Principal Quantum Number (n) specifies the energy of an electron and the size of the orbital. All orbitals that have the same value of n are said to be in the same shell (level).
The sSecondary, (Azimunthal) Quantum Number (l): l = 0, ..., n-1.
Specifies the shape of an orbital with a particular principal quantum number. The secondary quantum number divides the shells into smaller groups of orbitals called subshells (sublevels). Usually, a letter code is used to identify l to avoid confusion with n.
The principal and secondary quantum numbers are indicated for up to energy level four we can consult on a quantum number table
For the 1s we have that n=1 and l=0
For 2p we have that n=2 and l=1
For 4d we have n=4 and l=2
