In the context of quantum mechanics, the number of quanta is not limited in an atom. The term "quanta" refers to discrete packets of energy, and an atom can absorb or emit energy in multiple quanta.
The energy levels in an atom are quantized, meaning they can only have certain specific values. When an atom absorbs energy, an electron can transition from a lower energy level to a higher energy level by absorbing one or more quanta of energy. Similarly, when an electron moves from a higher energy level to a lower one, it emits energy in the form of quanta.
The number of quanta involved in these energy transitions depends on the energy difference between the initial and final states. The energy difference determines the number and frequency of quanta involved. For example, if the energy difference corresponds to the absorption or emission of a single quantum of energy, then only one quantum is involved. If the energy difference is larger, it could involve the absorption or emission of multiple quanta.
It's important to note that the term "quanta" is typically associated with the behavior of energy in quantum systems rather than a specific numerical quantity. The number of quanta involved in an energy transition can vary depending on the specific circumstances and energy differences involved.