The term "quantum number" can refer to different properties of an atom or particle, such as the electron configuration, spin, or magnetic moment. In the case of iron (Fe), if you are referring to the electron configuration, the quantum numbers associated with the last electron added to the atom are:
Principal quantum number (n): This quantum number describes the energy level or shell of the electron. For iron, the last electron is added to the 3d orbital, so the principal quantum number is 3.
Azimuthal quantum number (l): This quantum number defines the subshell or orbital shape. In the case of the 3d orbital, the azimuthal quantum number is 2.
Magnetic quantum number (m): This quantum number specifies the orientation of the orbital within a subshell. For the 3d orbital, the magnetic quantum number can take values from -2 to +2.
Spin quantum number (s): This quantum number describes the intrinsic angular momentum or spin of the electron. It can have two possible values: +1/2 (spin-up) or -1/2 (spin-down).
To summarize, for the last electron in the iron atom, the quantum numbers are:
n = 3 l = 2 m = (can take values from -2 to +2) s = (+1/2 or -1/2)