What Happens To An Electron In Its Ground State When It Absorbs A Photon Of Energy. From Start To Finish?

The electron absorbs a photon (in quantum mechanics, it is a quanta or packet of energy). The electron now has energy and is in an excited energy state. Any time after this occurs, the electron will spontaneously emit a photon, thus losing energy and returning to its ground state.

There are certain energy levels in an atom.An electron is a part of atom moving in its particular level.So when an electron absorbs energy ,it jumps to higher energy level from its groundstate.And when it emits energy it comes back to its original state.