How do Electrons Lose Energy?

I read in my high school text book that excited electrons release energy in the form of heat and light.Why cant they lose energy as sound or rather in any other form?
- Manisha Pandey (age 17)
Haldwani, Uttrakhand, India

For an isolated atom or molecule in a gas, excited states of electrons often don't have any easy way to lose energy except by electromagnetic radiation- light of some frequency. A little of the energy can go into internal vibrations for a molecule.  

In a liquid or solid, however, there are more ways to lose energy. For most excited states, direct electromagnetic radiation is still the biggest mode but it is often accompanied by some energy going into sound waves.

I'm not sure what the text means when it says that "heat" is one form. In solids and liquids, typical thermal energy ("heat") is in the form of sound waves. 

Mike W.

(published on 07/04/2015)