How does the line emission spectrum of an element relate to these flame tests?
Different elements will emit different wavelengths of light which correspond to different colors.
When an atom is exposed to high amounts of energy, its outer electrons, or valence electrons, absorb the energy by moving farther away from the nucleus. They then release the energy by moving closer to the nucleus. The greater this distance is, the more energy the light has and the shorter wavelength it will have.