Elements line spectrum?

Question

Can someone explain the relationship of an element's line spectrum colour and the "electron jumping back and forth energy level"?

Answer 1

When an electron in the outermost shell of an element absorbs energy it moves to a higher energy state. When moving to a lower energy state the energy is released. The wavelength of the released energy (light) is specific to each element. For example, when energy is released from hydrogen, the light is always the same wavelength and so scientists observing that radiation know it is coming from hydrogen and not some other element.

Answer 2

When an electron drops an energy level, the lost energy is emitted as a photon with the equivalent energy of the difference in the energy levels. A photon's energy is directly proportional to the photon's frequency.