When light emitted from low pressure gases is passed through a prism, a line spectrum emerges. This tells us that the energy associated with movements of electrons between energy levels is quantized.
The similarity between this and the harmonics in a pipe led to the the realisation that particles have wavelike properties (and vice versa). Electrons can be diffracted!
Key Concepts
Use quizzes to practise application of theory.
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The electron energy level model explains
each line in the spectrum corresponds to a different level energy transition
The diagram represents an electric field.
The path of an electron projected horizontally into this uniform electric field electric field is
The path is parabolic like that of a projectile on the Earth
The diagram represents an electric field.
The path of an electron projected vertically into this uniform electric field electric field is
The particle would have acceleration in the direction of motion but would not change direction.
A blue photon excites an electron from level 1 to level 2
What colour photon could excite an electron from 1 to 3
Higher energy means higher frequency. Violet has a higher frequency than blue.
The diagram represents the energy levels of a hydrogen atom
An electron jumps from A - B - C - D.
The photons are emitted in which order?
The smallest energy change leads to longest wavelength.
The diagram represents the energy levels of a hydrogen atom
An electron is excited from D to B when
The answer should be one UV photon is absorbed
To calculate the energy of a photon of frequency f you would use the formula
E = hf h is planks constant
The energy of a photon of visible light is approximately
The energy of a photon is about 1 eV this is the same as 1.6 x 10-19 J
The diagram represents 4 electron energy levels
Which energy photon could not be absorbed by this atom?
There is no transition where the difference is 0.5 eV
How much of Electron energy levels have you understood?
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