What is the significance of the terms - "isolated gaseous atom' and 'ground state' while defining the ionization enthalpy and electron gain enthalpy?

(a) The significance of term ‘isolated gaseous atom:’ When an atom is isolated in the gaseous state, its electron releasing tendency and electron accepting tendency are both absolute in nature. It means that their values of ionization enthalpy and of electron gain enthalpy are not influenced by the presence of the other atoms. It is not possible to express these when the atoms are in the liquid or solid state.

(b) The significance of ground state: As we know that both ionization enthalpy and electron gain enthalpy are related to the force binding the electrons with the nucleus of the atom, therefore these are related to the energy states of the atoms whether ground states or excited states.