The quantum numbers can be used to describe a specific electron in an atom of that element. There are four quantum numbers:
<span><span>n, the principal quantum number, which describes the shell of an electron;</span><span>l, the Azimuthal quantum number, which describes the subshell of an electron;</span><span><span>ml</span>, the magnetic quantum number, which describes/specifies the orbital an electron is in; and</span><span><span>ms</span>, the spin quantum number, which describes the spin of the electron.</span></span>
For example, if I was told that I had quantum numbers for a valence shell electron in the ground state for nitrogen were <span>n=2,l=1,<span>ml</span>=−1</span> and <span><span>ms</span>=+<span>12</span></span> then:
<span><span>The <span>n=2</span> tells me that we are describing a shell 2 electron.</span>the <span>l=1</span> describes the subshell as p.
I now know we are talking about a shell 2, p subshell energy level for the electron.The <span><span>ml</span>=−1</span> would indicate the specific orbital in the p-subshell (there are three possible p-orbitals in this p-subshell with <span>ml</span> values = -1, 0, +1)We have specified the first 2p-subshell orbital with the <span>ml</span> value = -1. The spin quantum number of +1/2 indicates one of two possible spin quantum numbers (+1/2 and -1/2) for the two electrons that can fill this specific orbital in this specific subshell and shell.</span>
