Question

How were electron shell energies first determined?

a. Observing the angle at which alpha particles scattered from gold foil.

b. Observing the voltage necessary to make small oil drops float in air.

c. Observing the discrete spectral emissions of hydrogen gas.

d. Observing the acceleration of electron beams in a magnetic field.

Answer 1

Ans:(c)Observing the discrete spectral emissions of hydrogen gas.

Explanation: It is by looking at the specific wavelengths of light that are either absorbed or emitted from a sample of H atoms, we discovered something about the energy of the electrons in the atom. Only specific wavelengths are associated with transitions. This means that there are discrete energy levels that the electron is moving between. The energy of the light of the transition corresponds to the difference in energy between two of these levels. If the energy of the electron is increasing, this is from absorption of the light energy. If the light is being emitted, this is from the energy of the electron decreasing.