$n$ (Principal Quantum Number): Defines the main energy level occupied by an electron in an atom and determines its relative distance from the nucleus.
$l$ (Azimuthal Quantum Number): Describes the shape of the orbital and subshell where an electron is located, ranging from 0 to $(n-1)$.
$m_l$ (Magnetic Quantum Number): Specifies the orientation of an orbital within a subshell, taking on integer values between $-l$ and $l$, inclusive.