The quantum numbers can be used to describe a specific electron in an atom of that element. There are four quantum numbers:
n, the principal quantum number, which describes the shell of an electron;l, the Azimuthal quantum number, which describes the subshell of an electron;ml, the magnetic quantum number, which describes/specifies the orbital an electron is in; andms, the spin quantum number, which describes the spin of the electron.For example, if I was told that I had quantum numbers for a valence shell electron in the ground state for nitrogen were n=2,l=1,ml=−1 and ms=+12 then:
The n=2 tells me that we are describing a shell 2 electron.the l=1 describes the subshell as p.