Si un atome d'hydrogène dans l'état fondamental absorbe un...

Si un atome d'hydrogène dans l'état fondamental absorbe un photon de longueur d'onde $\lambda_1$, puis émet un photon de longueur d'onde $\lambda_2$ sur quel niveau l'électron se trouve-t-il après cette émission? $$ \begin{aligned} & 1^{\text {er }} \text { cas : } \lambda_1=97,28 \mathrm{~nm} ; \lambda_2=1879 \mathrm{~nm} \\ & 2^{\mathrm{e}} \text { cas : } \lambda_1=97,28 \mathrm{~nm} ; \lambda_2=78,15 \mathrm{~nm} \end{aligned} $$

Si un atome d'hydrogène dans l'état fondamental absorbe un photon de longueur d'onde $\lambda_1$, puis émet un photon de longueur d'onde $\lambda_2$ sur quel niveau l'électron se trouve-t-il après cette émission?
$$
\begin{aligned}
& 1^{\text {er }} \text { cas : } \lambda_1=97,28 \mathrm{~nm} ; \lambda_2=1879 \mathrm{~nm} \\
& 2^{\mathrm{e}} \text { cas : } \lambda_1=97,28 \mathrm{~nm} ; \lambda_2=78,15 \mathrm{~nm}
\end{aligned}
$$

Key Concepts

Rydberg Formula

The Rydberg formula provides a way to calculate the wavelengths of the spectral lines of hydrogen by relating them to the difference in the inverse squares of the principal quantum numbers of the initial and final states. This formula is fundamental in understanding and predicting the spectral characteristics of hydrogen during electronic transitions.

Energy-Wavelength Relationship

The energy of a photon is directly related to its wavelength by the equation E = hc/?, where h is Planck’s constant and c is the speed of light. This relationship is crucial in analyzing transitions in atoms because it allows us to determine the energy differences between quantum levels from the measured wavelengths of absorption or emission.

Photon Absorption and Emission

When an electron absorbs a photon, it gains energy and moves from a lower energy level to a higher one. Conversely, when it emits a photon, the electron loses energy and transitions to a lower energy state. These processes are governed by the conservation of energy, where the energy of the photon must match the difference between the atomic energy levels.

Quantum Energy Levels

This concept refers to the idea that electrons in an atom can only occupy certain discrete energy states. In hydrogen, these levels are characterized by a principal quantum number, and transitions between these states occur when the electron absorbs or emits a photon whose energy corresponds to the difference between the two levels.

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