Bohr Model of Hydrogen
Recommended Reading
Learning Objectives
By the end of this section, you will be able to:
- Describe the Bohr model of the hydrogen atom and explain its significance.
- Explain electron transitions and how they result in the emission of characteristic photons and Auger electrons.
- Understand and apply the photon model for electromagnetic radiation, including the relationship between photon energy and wavelength.
Emission and Absorption Spectra
Rydberg Formula for Hydrogen:
Practice!
| Practice 2.1.1 |
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| A hydrogen atom makes a transition from the n = 3 level to the n = 2 level. It then makes a transition from the n = 2 level to the n = 1 level. Which transition results in emission of the longest-wavelength photon? |
| Practice 2.1.2 |
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| Which of the following observations led Bohr to formulate his model of the hydrogen atom? |
Bohr’s Model for Hydrogen
Quantized Radii of the Hydrogen Atom:
Quantized Energies of the Hydrogen Atom:
Practice!
| Practice 2.1.3 |
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| What was Bohr’s quantum condition on the orbital energies in an atom? |
| Practice 2.1.4 |
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| A hydrogen atom is in its ground state. Incident on the atom are many photons each having energy of 10.5 eV. The result is which of the following? |
Discuss!
Reflect on these questions and take notes on how you would answer them. Then we will share these thoughts together in a class discussion.
A hydrogen atom initially in its ground state absorbs a photon, which excites the atom to the n = 3 level. Determine the wavelength and frequency of the photon.
The n = 3 state of hydrogen has E3 = -1.51 eV.
(a) Why is the energy negative?
(b) What is the physical significance of the specific number 1.51 eV?
Draw and label an energy level diagram for hydrogen. On it, show all the transitions by which an electron in the n = 4 state could emit a photon.
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