The energy levels of hydrogen atoms are quantized, meaning they can only exist at specific, discrete values. This phenomenon arises from the wave-like nature of electrons within atoms and the constructive and destructive interference of their waves. Each energy level corresponds to a specific orbital, which describes the spatial distribution of the electron. The lowest energy level, known as the ground state, has an energy of -13.6 electronvolts (eV). Excited states have higher energies and are labeled by their principal quantum number (n), which ranges from 2 to infinity. Transitions between energy levels result in the emission or absorption of photons with energies corresponding to the energy difference between the levels.