How an electron in an atom emits photons that make light?

Answer 1

Electrons are bound to atomic nuclei in quantum electron orbitals which have definite energy levels. When an electron decides to vacate one orbital and take up house in another, it involves a change of energy, which, if given up, become manifest in the form of photon energy. It's a way of "dumping energy" without giving up mass. The reverse is that an electron absorbs energy from an incoming photon to give it energy necessary to move to another electron orbital, one wtth a higher energy state.

Answer 2

When an atom absorbs energy (usually a photon) from another source, an electron can be moved into a more excited state - an orbital that is further out. But, because this is an unstable position, the electron quickly falls back to its ground state. In doing so, it radiates off the energy that is the energy difference between the electron's excited state and the ground (lowest energy) state.

Answer 3

An electron can change its orbit to a lower or a higher energy state. To change to a higher energy state, it requires an infusion of energy. To change to a lower energy state, it releases excess energy, as a photon.