AP Chemistry Flashcards: Properties of Photons
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Review key ideas with interactive flashcards. This set includes 10 cards to help you master important concepts.
How is a photon's energy related to its frequency?
A photon's energy is directly proportional to its frequency, as described by the equation E = hν.
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How is a photon's energy related to its frequency?
A photon's energy is directly proportional to its frequency, as described by the equation E = hν.
Summarize the energy exchange when an atom or molecule interacts with a photon.
When an atom or molecule absorbs or emits a photon, its energy changes by an amount precisely equal to the energy of that photon.
What equation relates the speed of light, wavelength, and frequency?
The equation c = λν relates the speed of light (c) to wavelength (λ) and frequency (ν).
What occurs within an atom or molecule when it emits a photon?
When an atom or molecule emits a photon, it undergoes an electronic transition where its total energy decreases.
What is the relationship between an electronic transition in an atom and the energy of an emitted photon?
The energy of an emitted photon is equal to the decrease in energy the atom experiences during the electronic transition.
An atom's energy decreases by a specific amount, ΔE, during an electronic transition. What is the energy of the photon that is emitted?
The energy of the emitted photon is exactly equal to the amount of energy the atom lost, ΔE.
What happens to an atom's energy when it absorbs a photon?
When an atom absorbs a photon, its energy increases by an amount exactly equal to the photon's energy.
What is Planck's equation?
Planck's equation relates the energy of a photon to its frequency: E = hν.
Using the relationship c = λν, describe the frequency of light that has a long wavelength.
Since wavelength and frequency are inversely proportional, light with a long wavelength (λ) must have a low frequency (ν).
If a photon has a very high frequency, what can be concluded about its energy?
According to Planck's equation (E = hν), a photon with a high frequency will also have a high energy.