Flame Tests and
Atomic Emission Spectroscopy

Pre-lab Questions

Answer the following questions and perform the following calculations.

1. What is the emission spectrum of an element?
2. What do the lines in an emission spectrum of an element represent?
3. Define the terms ground state and excited state and explain how an electron moves from ground to excited and back again.
4. Given the wavelength of a line in an atomic emission spectrum, how do you calculate the energy of the photons released to make that line?
5. What is the relationship between the color of a line in an atomic emission spectrum and what is happening inside the atoms?
6. The element helium (He) has lines in its visible spectrum at 389 nm, 447 nm, 588 nm, and 707 nm. Calculate the frequency in Hz for each of these lines. (1 m = 1 × 10⁹ nm).
7. For each of the spectral lines in the previous problem calculate the energy in Joules of the photons emitted by helium atoms to make the lines.