### Rydberg Equation

Posted:

**Wed Jul 31, 2019 2:02 am**in the rydberg equation En= (-hR)/(n^2) why is there a negative included?

Created by Dr. Laurence Lavelle

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

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=17&t=45645

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Posted: **Wed Jul 31, 2019 2:02 am**

in the rydberg equation En= (-hR)/(n^2) why is there a negative included?

Posted: **Wed Jul 31, 2019 8:30 am**

Rydberg Equation: 1/λ=R(1/n(1)^2−1/n(2)^2)

You can change n(1) and n(2), which refer to different energy levels in the Hydrogen atom. For example, you can use n(1)= 1 and n(2)=2 to find the wavelength of light emitted when an electron drops from the n=2 to the n=1 energy level (or the wavelength of light needed to excite from 1 to 2). You can change n(2) to n(2)= 3 to find the wavelength emitted when the electron drops from n=3 to n=1 instead.

You can change n(1) and n(2), which refer to different energy levels in the Hydrogen atom. For example, you can use n(1)= 1 and n(2)=2 to find the wavelength of light emitted when an electron drops from the n=2 to the n=1 energy level (or the wavelength of light needed to excite from 1 to 2). You can change n(2) to n(2)= 3 to find the wavelength emitted when the electron drops from n=3 to n=1 instead.

Posted: **Thu Oct 10, 2019 12:06 pm**

Chem_Mod wrote:Rydberg Equation: 1/λ=R(1/n(1)^2−1/n(2)^2)

You can change n(1) and n(2), which refer to different energy levels in the Hydrogen atom. For example, you can use n(1)= 1 and n(2)=2 to find the wavelength of light emitted when an electron drops from the n=2 to the n=1 energy levIel (or the wavelength of light needed to excite from 1 to 2). You can change n(2) to n(2)= 3 to find the wavelength emitted when the electron drops from n=3 to n=1 instead.

Sorry, I have two clarification questions:

1) why does the equation use 1/λ instead of c/λ, which is equivalent to frequency?

2) In the equation you've written, between n

Posted: **Fri Oct 11, 2019 8:53 am**

Jocelyn Thorp 3K wrote:Chem_Mod wrote:Rydberg Equation: 1/λ=R(1/n(1)^2−1/n(2)^2)

You can change n(1) and n(2), which refer to different energy levels in the Hydrogen atom. For example, you can use n(1)= 1 and n(2)=2 to find the wavelength of light emitted when an electron drops from the n=2 to the n=1 energy levIel (or the wavelength of light needed to excite from 1 to 2). You can change n(2) to n(2)= 3 to find the wavelength emitted when the electron drops from n=3 to n=1 instead.

Sorry, I have two clarification questions:

1) why does the equation use 1/λ instead of c/λ, which is equivalent to frequency?

2) In the equation you've written, between n_{1}and n_{2}(both of which are squared), which is the initial state and which is the final state? I'm assuming n_{2}is final and n_{1}is initial but I'd like to be sure.

your assumption that n