What do you mean by quantization of electronic energy and angular momentum?

Hint: First we need to know the definition of quantization. Where the quantization is the process of constraining an input form a continuous or otherwise we can say that large scale values to a discrete set. Quantization of electric energy is also known as quantized energy.

Complete answer:
Here we need to state what we meant by quantization of electronic energy and angular momentum.
Quantization of electronic energy: Quantized energy means that the electrons can possess only a certain amount of discrete energy values and the values in between those quantized values are not permitted. This is because of the quantized orbits such as the quantum jumps which will produce discrete spectra in agreement with observation.

Quantization of angular momentum: Quantization of angular momentum means that the radius of the orbit and the energy will be quantized as well. The scientist Bohr assumed that the discrete lines seen in the spectrum of the hydrogen atom and these discrete lines were due to the transitions of an electron from one allowed orbit or we can say that energy to another.

Note: Remember that the energy of quantization is important because of the relationship between the energy levels and the spectra that we can observe by doing experiments. Also keep in mind that the angular momentum operator plays a central role in the theory of atomic and molecular physics and at the same time another quantum problem that involves rotational symmetry also comes under angular momentum.