When an electron jumps from a higher energy level (shell) to a lower energy level within an atom, it emits energy in the form of electromagnetic radiation. This process is known as an electronic transition or an electron transition. The energy emitted corresponds to the difference in energy between the initial and final energy levels of the electron.
The energy levels of electrons in an atom are quantized, meaning they can only occupy specific energy states. These energy states are determined by the atom's electronic structure and the behavior of electrons in the atom's potential well created by the nucleus.
When an electron is in a higher energy level, it is in an excited state. Excited states are less stable than lower energy levels, which are called ground states. The electron naturally tends to move toward a more stable configuration, which involves transitioning to a lower energy level.
According to quantum mechanics, the energy of an electron in an atom is related to its orbital configuration. Electrons in different energy levels occupy different orbitals, which are regions around the nucleus where electrons are likely to be found. As an electron transitions from a higher energy level to a lower energy level, it moves to an orbital closer to the nucleus.
During this transition, the electron's energy decreases, and conservation of energy requires that the energy difference be released in another form. This energy is emitted as a photon, which is a discrete packet of electromagnetic radiation. The energy of the photon corresponds exactly to the energy difference between the initial and final energy levels of the electron.
The relationship between the energy of a photon and its wavelength (or frequency) is given by Planck's equation: E = hf, where E is the energy of the photon, h is Planck's constant, and f is the frequency of the electromagnetic radiation. The emitted photon carries away the energy difference, accounting for the decrease in energy of the electron.
Overall, an electron loses energy when it jumps from a higher to a lower shell due to the transition to a more stable configuration, and this energy is emitted as electromagnetic radiation in the form of photons.