when an atom is in an excited state, the electron can drop all the way to the ground state in one go, or stop on the way in an intermediate level. electrons do not stay in excited states for very long - they soon return to their ground states, emitting a photon with the same energy as the one that was absorbed.
hi my dear friend,
because we must add heat, boiling water is a process that chemists call endothermic. clearly, if some processes require heat, others must give off heat when they take place. changes of state involve a solid melting, a liquid freezing, a liquid boiling or a gas condensing.