How is the light emitted by an atom related to its electron configuration?

i've been struggling to figure out how exactly to answer this. i believe it has something to do with the electrons becoming excited and changing orbitals, but that's all i've really got..

Electrons in an atom exist in fixed energy states (quanta) called shells, each shell is given a quantum number which refers to how much energy an electron will have to have if it is to exist in that particular shell, the higher the quantum number the higher the energy. 

I'm not sure but i will try to find out