### Why don't we use the Rydberg equation from the book?

Posted:

**Sun Oct 15, 2017 7:50 pm**I was curious as to why we don't use the Rydberg equation from the book and why it is better to use -hR/n^2? Doesn't it kind of do the same thing?

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=17&t=22280

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Posted: **Sun Oct 15, 2017 7:50 pm**

I was curious as to why we don't use the Rydberg equation from the book and why it is better to use -hR/n^2? Doesn't it kind of do the same thing?

Posted: **Sun Oct 15, 2017 8:13 pm**

It does the same exact thing. Dr. Lavelle said he doesn't prefer the equation in the book because students were getting confused on which place to put the final and initial energy levels whereas the delta E equation is more clear and straight forward AND tells you which direction the energy is going in. If you prefer the book equation, that works too.

Posted: **Sun Oct 15, 2017 10:02 pm**

Building on that question, the Rydberg equation is applicable to atoms of different elements, but the other equation -hR/n^2 is only applicable to hydrogen atoms, correct?

Posted: **Sun Oct 15, 2017 10:41 pm**

The Rydberg equation given in the text book is a derivation of the formula given by Dr. Lavelle. He said we can use it if we understand the way it was created.

Posted: **Sun Oct 15, 2017 10:42 pm**

No the equation given in the book also is only useful for hydrogen related purposes.

Posted: **Sun Oct 15, 2017 11:13 pm**

For the purposes of the class will we be learning similar equations for different atoms? I understand the Rydberg equation is based off empirical data for the H-atom, however did Dr. Lavelle mention anything about one for other atoms?

Posted: **Tue Oct 17, 2017 4:49 pm**

Dr Lavelle hasn't talked about similar equations for other atoms, and we wouldn't be expected to know them, at least at our current level.

Posted: **Tue Oct 17, 2017 9:47 pm**

I think Dr. Lavelle said he doesn't want us to use it because it doesn't make conceptual sense. You can derive the one from the textbook from the formula from class though and plug it into the change of energy = energy(final) - energy(initial). If you wanna use the one from the textbook I've heard you won't get partial credit.

Posted: **Wed Oct 18, 2017 10:45 pm**

There are also times where it would be faster to use the formula that the book had given us, which would be why they included it in the first place. However, the formula from the lecture better illustrates what is occurring as the change from one level to another occurs. If a question asked specifically for the velocity of the light, we could use the formula for the book, but you could also obtain the answer by following the lecture's equation and then solving for v by the formula E=hv