# Homework Help: The emission spectrum of an unknown element

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1. Sep 24, 2017

### Specter

1. The problem statement, all variables and given/known data
The emission spectrum of an unknown element contains two lines - one in the visible portion of the spectrum, and the other, ultraviolet. Based on the following figure and what you have learned about Niels Bohr's model of the atom, account for the difference in energy between the lines.

The diagram given in the question.

2. Relevant equations
None

3. The attempt at a solution

The difference in energy between these lines is the result of electrons transitioning from higher orbitals to lower orbitals.The electron transition responsible for ultraviolt light is falling a great distance in the atom creating higer energy and shorter wavelengths.

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I'm not sure if this is correct or not, we didn't really learn much about this in the lesson.
Is there anything I should research to help me better understand the question? Is there anything I should correct in my answer?

Thanks!

2. Sep 24, 2017

### Staff: Mentor

What do you mean by "distance"?

3. Sep 24, 2017

### Specter

The electron transition responsible for ultraviolet light jumps to an orbital and the attraction of the nucleus pulls the electron back to a lower energy. The energy that the electron absorbed is emitted, creating short wavelengths and high energy.

Does this make more sense?

4. Sep 24, 2017

### Staff: Mentor

What does the word "distance" mean?
If it refers to anything in space, it is wrong.
That doesn't make sense. The electric attraction is what determines the energy of all energy levels. It doesn't "pull things to lower energy levels".

5. Sep 25, 2017

### Specter

What I read in my lesson is this:

"The attraction of the nucleus eventually pulls the electron back to a lower energy level. When it does, the energy that the electron absorbed is emitted. The energy emitted by the atom is the difference in energy between the two energy levels that the electron occupied."

This is about all there is about spectroscopy in this lesson. Everything else is about energy level diagrams and electron configurations.

Is this referring to something different then what the question is asking me to answer? Isn't this saying that the electron jumping to a higher orbital and being pulled back to a lower energy level is what causes the difference in energy?

By distance I mean the electron transitioning from a higher orbital to a lower orbital. An example would be an electron transition from orbital 6 to orbital 2.

I am still confused by this. I have tried finding some info online and I read the lesson multiple times.

6. Sep 25, 2017

### Staff: Mentor

Perhaps part of the problem is the communication here. When we say "higher orbital" and "lower orbital", we don't mean them to be higher and lower as - say - bird and plane. Higher orbital is in general not "more distant" from the nucleus (as opposed to the higher flying plane being more distant from the Earth surface). So the word "distance" in this context can be a bit confusing and is better to be avoided.

7. Sep 25, 2017

### Specter

Thanks.

So the difference in energy between the lines is the electron transition from a higher orbital to a lower orbital? For example, if an electron transitions from orbital 6 to orbital 3, would the energy be greater than an electron transition from orbital 6 to orbital 4?

8. Sep 25, 2017

Right.