Orbital question?

Question

Explain why you see the color green when copper ions are heated in a flame. What orbitals might the excited electrons be jumping between?

Answer 1

A simple explanation in words only, without getting into the math:

 

An atom radiates energy when an electron jumps from a higher to a lower energy orbital.  The frequency and wavelength of the radiated energy depends on the difference in energy between the two orbitals.  If the atom emits in the green region of the electromagnetic spectrum, then the difference in energy between the orbitals corresponds to the energy of a photon of light whose frequency and wavelength are in the green region of the electromagnetic spectrum.