Ground state vs excited state

Answer 1

A ground state is an outer orbital electron of an element that is at its lowest possible energy level. The electron in an excited state has a higher energy level than a ground state electron. The average distance from the nucleus is greater in the excited state than in the ground state.

Answer 2

In simplest way we can say that ground state of an atom is when an atom has normal arrangement of electrons in its respective energy orbits. When electrons are excited from the ground state by absorbing a photon, electrons gains energy and it jumps to the next high energy orbit. But since this is very unstable state electron drops down to its ground state and in process emitting electromagnetic radiation.

Answer 3

Similarly to electrons in an atom, nuclear isotopes are only allowed to have specific, discrete amounts of energy, called quanta. The lowest quanta of energy in these situations are called the ground state. Any higher allowed energy value is an excited state. The natural desire for an electron or nucleus to be in its ground state is the reason behind some cool phenomena like x-ray and gamma radiation, which are specific quantas of energy released by an electron or nucleus, in the form of a photon, whose energy is equal to the difference between the energy of an excited state and that of a lower state, including the ground state.