What is an excited state electron configuration?

An excited state electron configuration refers to an atom with electrons at a higher energy level than is necessary. An excited state differs from a ground state, which is when all of the atom's electrons are in the their lowest possible orbital.

For example, an atom in an excited state may contain two electrons in its 1s orbital, one electron in its 2s orbital and one electron in each of its 2p orbitals. Since the maximum possible number of electrons in the 2s orbital is two electrons, one of the electrons in a 2p orbital needs to move to the 2s orbital to return the atom to a ground state.