Krypton atoms emit orange light when they are excited and then return to their ground state. This phenomenon occurs due to the specific energy levels and electronic transitions within the krypton atom.
When a krypton atom is energized, typically by passing an electric current through a krypton gas discharge tube, the atoms absorb energy. This energy excites the electrons in the atom, causing them to move to higher energy levels or orbitals. These excited electrons are in an unstable state and will eventually transition back to their lower energy levels.
During this transition, the excited electrons release energy in the form of light. In the case of krypton, this light is predominantly in the orange part of the visible spectrum. The specific wavelength of the emitted light corresponds to the energy difference between the excited state and the ground state of the atom. In the case of krypton, this energy difference corresponds to orange light.
It's worth noting that the color emitted by an atom or gas depends on its unique electronic structure and energy levels. Different atoms or gases will emit different colors of light when excited, based on their specific energy transitions.