What is the colour of the light associated with the line emission spectrum of sodium? Explain how line emission spectra occur - Leaving Cert Chemistry - Question (b) - 2002

Line emission spectra occur through the interaction of electrons with energy levels in atoms. When an atom absorbs energy, its electrons can become excited, moving from a lower energy level to a higher one. This process can be visualized in an energy level diagram.

When these electrons fall back to their original energy levels, they release the energy difference as light, which can be measured as specific wavelengths in the spectrum. The relationship between the energy difference (E) and frequency (ν) of the emitted light can be described by the equation:
$E = hν$
where h is Planck's constant. Each transition results in a line in the emission spectrum that corresponds to a specific wavelength.

Line emission spectra provide evidence for the existence of discrete energy levels in atoms. Each element emits light at characteristic wavelengths, indicating that electrons occupy specific energy states.
These fixed frequencies, or lines in the spectrum, correspond to the differences between the energy levels and support the concept of quantized energy states, as demonstrated by observed spectral lines from hydrogen and other elements.

It is possible for line emission spectra to distinguish between different elements because each element's electrons are structured uniquely, leading to unique sets of energy levels. As a result, each element emits a distinct spectral line pattern, which acts like a 'fingerprint'. By analyzing the line emission spectra, one can identify specific elements based on their unique spectral characteristics and energy distributions.