Give an example of a physical entity that is quantized. State specifically what the entity is and what the limits are on its values.

The meaning that something is quantized or some entity is quantized that is this thing is restricted for the values it gets for its energy, charge, position and many other things.

Like the electron in the atom or the molecule, its energy is quantized; it cannot get any value of energy but those which are equal to the energy level in the atom.

The limit for this quantization depends on the scale you are dealing with. If we deal with the atomic scale we will see the energy is quantized, while if we go to the macroscopic scale we will see that the energy is continuous.

To imagine that, think in the tap water it seems like it is continuous but you know that it consists of many drops of water and if you closed the tap you will see these drops. It is the same for energy.

The Example is: The energy of an electron in an atom.

Therefore, the limits for the values are depending on the atomic shells for the atom.