Angular quantum number is a quantum number related to energy. From the concept of classical mechanics, any Revolver All have axial angular momentum 。 
Angular quantum number It is a vector. When it does not change continuously, it will take different Separation value Is quantized.
The angular quantum number l determines the shape of the atomic orbit and determines the energy level of the electron in a multi electron atom together with the main quantum number. The motion of electrons around the nucleus not only has certain energy, but also has certain angular momentum M. Its size is closely related to the shape of the atomic orbit. For example, when M=0, that is, when l=0, it means that the motion of electrons in the atom is independent of the angle, that is, the atomic orbit is spherically symmetric; If l=1, the atomic orbits are dumbbell shaped; If l=2, it is petal shaped. For a given n value, quantum mechanics proves that l can only take a positive integer less than n: l=0,1,2,3... (n-1) magnetic quantum number m magnetic quantum number m determines the orientation of atomic orbit in space. The atomic orbits of a certain shape can be stretched in different directions in space, thus obtaining several atomic orbits with different spatial orientations.
This is based on the fact that the linear spectrum can still split in the magnetic field, showing a small energy difference. The magnetic quantum number can be taken as m=0, ± 1, ± 2...... ± l spin quantum number m s Directly from Schrodinger equation The fourth quantum number - spin quantum number m is not available s , which was introduced according to the later theoretical and experimental requirements. Precise observation of atomic spectra in the presence of a strong magnetic field shows that most spectral lines are actually composed of two spectral lines close together. This is because when electrons move outside the nucleus, they can also take two motion states with the same value and opposite direction, usually represented by ↑ and ↓ Angular quantum number [1] (azimuthal quantum number) is introduced because when the electron moves around the nucleus, it not only has certain energy, but also has certain angular momentum. The relationship between the absolute value of angular momentum and the angular quantum number l is as follows:
For a given value of n, quantum mechanics It is proved that l can only take non negative integers less than n: l=0,1,2,3... (n-1). horn Quantum number Determining the movement of electrons in space angular momentum , and Atomic orbital or Electronic cloud The shape of Principal quantum number N jointly determines the electron energy. For a certain n value, l can take a total of n values such as 0, 1, 2, 3, 4... n-1, which are represented by spectroscopic symbols as s, p, d, f, g, etc. The angular quantum number l represents the sublayer or energy level of the electron. One n value can have multiple l values, for example, n=3 means the third Electronic layer , l values can be 0, 1, 2, respectively representing 3s, 3p, 3d sublayers, and the corresponding electrons are called 3s, 3p, 3d electrons respectively. Their atomic orbits and electron clouds are spherical symmetry, dumbbell shaped and four petal plum shaped, respectively. For multi electron atoms, the energy of these three sub layers is E3d>E3p>E3s, that is, when the n value is fixed, the greater the l value, the higher the energy level of the sub layer. When describing the energy state of a multi electron atomic system, it is necessary to use two Quantum number 。 
Angular quantum number
