### Rydberg constant

Posted:

**Sat Oct 13, 2018 6:28 pm**Does anyone know when to use the Rydberg constant?

Created by Dr. Laurence Lavelle

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

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=27&t=33750

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Posted: **Sat Oct 13, 2018 6:28 pm**

Does anyone know when to use the Rydberg constant?

Posted: **Sat Oct 13, 2018 6:51 pm**

You use the Rydberg constant when you are solving for the energy change when an electron changes energy levels.

Posted: **Sat Oct 13, 2018 10:10 pm**

The equation is ΔE= -(h x R)/n²

When you are calculating the energy difference between an electron that has gone from n=4 to n=2 (emitting light), you find ΔE for n=4, n=2 and then you subtract the difference. In this case, it would be ΔE for when n=2 - ΔE for when n=4, as it is final - initial, and the final energy level of the electron is 2.

When you are calculating the energy difference between an electron that has gone from n=4 to n=2 (emitting light), you find ΔE for n=4, n=2 and then you subtract the difference. In this case, it would be ΔE for when n=2 - ΔE for when n=4, as it is final - initial, and the final energy level of the electron is 2.

Posted: **Sun Oct 14, 2018 8:48 pm**

Rydberg constant has been only really been shown to be used in context of the Rydberg equation in this chapter thus far. Like the poster above has stated, it is used to calculate the energy released from electrons in a hydrogen atom while undergoing spectroscopy (NOTE: this equation is specifically tailored to Hydrogen, since it has the simplest electron structure of any element).

In class, Lavelle has encouraged the usage of the equation E= hR / n^{2} for each n value, then subtracting the difference. This is a very straightforward equation and requires very few inferences to get a final result; simply find values and subtract the smaller number from the larger one.

In the textbook on the other hand, there exists a singular equation that combines these steps in one, so long as you carefully consider the order of n-values:

E = R( 1/n_{initial}^{2} - 1/n_{final}^{2}), where n_{initial} is the higher value n-level and n_{final} is the lower energy n-value. The final result of this one equation should be the same as the process labeled above, but it is easy to go awry. Use at your own risk!

In class, Lavelle has encouraged the usage of the equation E= hR / n

In the textbook on the other hand, there exists a singular equation that combines these steps in one, so long as you carefully consider the order of n-values:

E = R( 1/n

Posted: **Sun Oct 14, 2018 8:56 pm**

I believe Dr. Lavelle stated that the Rydberg equation is used specifically for hydrogen ions, but there was an exception for helium as long as it had one electron. The equation is to be used for atoms that have one electron which is why it is almost exclusively used for hydrogen atoms

Posted: **Mon Oct 15, 2018 11:10 pm**

The Rydberg constant (3.29 times 10 to the 15th hz) is used in the equation that can give the energy of a hydrogen electron. E equals -h times R over n squared where n is the energy level. Remember this equation only works for Hydrogen atoms.

Posted: **Mon Oct 15, 2018 11:40 pm**

Bianca Barcelo 1G wrote:Does anyone know when to use the Rydberg constant?

you use it when you're solving for an energy change

Posted: **Tue Oct 16, 2018 2:31 pm**

Lavelle did not go over the equation for energy level changes during lecture but explained how to implement the constant without having to memorize the formula.