# Bohr Model - Absorbing a Photon with Enough Energy to Ionize the Atom

• flintstones
In summary: But again, I'm just confused about something.Any photon with an energy of more than 5.1 eV that passes through a sodium atom gets absorbed.
flintstones
Homework Statement
What happens when a photon has more than enough energy to ionize an atom? Can it be absorbed?
Relevant Equations
N/A
I just want to confirm something. You need about 13.6 eV of energy to ionize a hydrogen atom in the ground state.

Can the atom absorb a photon with 15 eV of energy? I think it can. This would free the electron, and the freed electron would move off with a kinetic energy of 15 minus 13.6 eV, correct?

I checked two textbooks and both only say that an atom can only absorb a photon with an energy that corresponds to the difference between the atom's energy levels.

Neither mentions the case where a photon has more than enough energy to ionize an atom, so I just want to make sure I'm not thinking incorrectly.

E_ph=hf=DeltaE(Atom)+E_kin(electron)

The photon should be completely absorbed.The rest energy goes into the kinetic Energy of the electron after it has leaved the ionised Atom as I stated in the formula above.

Last edited:
flintstones said:
Homework Statement:: What happens when a photon has more than enough energy to ionize an atom? Can it be absorbed?
Relevant Equations:: N/A

checked two textbooks and both only say that an atom can only absorb a photon with an energy that corresponds to the difference between the atom's energy levels.
The bound energy levels exist from -13.6 eV to zero. Beyond that, there is continuum of energy levels where the electron can exist. So yes, a 15 eV photon will ionize an electron which will acquire 1.4 eV of kinetic energy.

kuruman said:
The bound energy levels exist from -13.6 eV to zero. Beyond that, there is continuum of energy levels where the electron can exist. So yes, a 15 eV photon will ionize an electron which will acquire 1.4 eV of kinetic energy.
Thanks, this is what I thought. But now I'm confused about something else.

Take the sodium atom for example. The energy levels go from approximately -5.1 eV to zero. So photons with an energy of more than 5.1 eV should ionize the atom and be absorbed.

Does this mean ANY photon with an energy of more than 5.1 eV that passes through a sodium atom gets absorbed? Because that doesn't seem right...

It's not as simple as that. Sodium has many more electrons than hydrogen that can be be ionized. They are in energy levels with energies less than -5.1 eV. I would think that any photon with energy more than 5.1 eV could ionize the outer electron.

## 1. What is the Bohr Model?

The Bohr Model is a simplified representation of the structure of an atom, proposed by Niels Bohr in 1913. It states that electrons orbit the nucleus in specific energy levels, and can jump between levels by absorbing or emitting photons.

## 2. How does the Bohr Model explain ionization?

The Bohr Model explains ionization as the process of an electron in an atom absorbing a photon with enough energy to jump to a higher energy level or completely leave the atom. This results in an ion, or a charged atom, as it now has an unequal number of protons and electrons.

## 3. What is the minimum energy required for ionization in the Bohr Model?

The minimum energy required for ionization in the Bohr Model is known as the ionization energy. This energy is different for each element and is dependent on the number of protons in the nucleus and the distance between the nucleus and the electron.

## 4. How does the Bohr Model explain the absorption of a photon with enough energy to ionize an atom?

In the Bohr Model, electrons are in specific energy levels and can only absorb photons with energy equal to the difference between two energy levels. When a photon with enough energy is absorbed, the electron jumps to a higher energy level or leaves the atom entirely, resulting in ionization.

## 5. How does the Bohr Model relate to modern atomic theory?

The Bohr Model was an important step in the development of modern atomic theory, as it introduced the concept of energy levels and quantized energy in atoms. However, it is now known to be an oversimplified model and has been replaced by more accurate models, such as the quantum mechanical model.

• Introductory Physics Homework Help
Replies
2
Views
861
• Introductory Physics Homework Help
Replies
3
Views
1K
• Introductory Physics Homework Help
Replies
9
Views
1K
• Introductory Physics Homework Help
Replies
4
Views
1K
• Introductory Physics Homework Help
Replies
35
Views
1K
• Introductory Physics Homework Help
Replies
3
Views
785
• Introductory Physics Homework Help
Replies
1
Views
981
• Introductory Physics Homework Help
Replies
2
Views
1K
• Introductory Physics Homework Help
Replies
11
Views
2K
• Atomic and Condensed Matter
Replies
23
Views
2K