Question

relating this information back to the flame test and light emission lab: 1. in the experiment, where were the atoms getting their excess energy from? 2. in the flame test, we see different colors. what are we seeing? are we seeing the different bands separately or will we see an overall color? 3. why do you think different atoms emit different colors of light?

Explanation:

1. In a flame - test, the heat from the flame provides the excess energy to the atoms. The flame is a source of thermal energy which excites the electrons in the atoms.
2. We see an overall color in the flame test. The different spectral lines (bands) combine in our eyes and brain to form a single, overall color impression. The human eye is not able to distinguish the individual spectral lines in most cases during a simple flame - test setup.
3. Different atoms emit different colors of light because each atom has a unique set of energy levels for its electrons. When an excited electron returns to a lower energy level, it emits a photon of light with an energy corresponding to the energy difference between the two levels. Since the energy levels are unique for each element, the energy (and thus the color, as color is related to the wavelength and energy of light) of the emitted photons is also unique.

Answer:

1. The heat from the flame.
2. We see an overall color.
3. Because each atom has a unique set of energy levels for its electrons.