Which electronic level would allow the hydrogen atom to absorb a photon but not to emit a photon
Ans) We know the energy of electron goes on to become more negative as it reaches 1st level energy. the energy is least at the 1st electronic level and most negative at which the atom can only absorb energy or photons but cannot emit since its in the stable state.emission requires a more lower electronic level to be present so that the electron can jump to it after emtting energy or photons.HENCE,the 1st electronic level would allow the hydrogen atom to absorb a photon but not to emit it.