Question

Where do the four atomic quantum numbers come from?

Answer 1

See below.

Explanation:

Niels Bohr in 1913 was the first person to introduce a quantum number.

The Bohr model used only a single quantum number `n` to specify the energy levels and hence the size of the two-dimensional orbits in which the electrons traveled.

In 1925, Erwin Schrödinger developed his three-dimensional quantum mechanical model of the atom.

He introduced three quantum numbers:

• `n`, the principal quantum number, which specified the energy and size of the orbital.
• `l`, the azimuthal quantum number, which specified the shape of the orbital
• `m_l`, the magnetic quantum number, which specified the orientation of the orbital in a magnetic field.

Also in 1925, George Uhlenbeck and Samuel Goudsmit introduced a fourth quantum number, called the spin quantum number `s` of an electron.

And that’s where our four quantum numbers come from.