Final answer:
Quantized energy levels mean that energy in a system can only have specific, distinct values, with no values allowed in between. This principle is key in quantum physics, affecting how electrons transition and interact within an atom.
Step-by-step explanation:
When energy levels are quantized, it means that in certain physical systems, such as the atoms in an electron cloud, energy can exist only at specific, discrete levels. Unlike what classical physics suggest, energy levels aren’t continuous, but have clear-cut, separated values that energy can take. One may imagine it as if energy were available only in distinct packets or bundles, much like a staircase has individual steps. When electrons transition between these levels, they absorb or emit energy in discrete lumps, corresponding to the gap between these quantized levels. This quantized nature of energy levels is a foundational principle in quantum physics and chemistry, as it helps describe phenomena such as atomic emission spectra and the workings of lasers.