## Rydberg Equation

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duenezjuleny1D
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### Rydberg Equation

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

Chem_Mod
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### Re: Rydberg Equation

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.

Jocelyn Thorp 1A
Posts: 103
Joined: Wed Sep 18, 2019 12:20 am

### Re: Rydberg Equation

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 n1 and n2 (both of which are squared), which is the initial state and which is the final state? I'm assuming n2 is final and n1 is initial but I'd like to be sure.

805097738
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### Re: Rydberg Equation

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 n1 and n2 (both of which are squared), which is the initial state and which is the final state? I'm assuming n2 is final and n1 is initial but I'd like to be sure.

your assumption that n2 is final and n1 is initial is correct. Lavelle went over the derivation in class to make sense of this equation ans explain how to arrive at it but it was a very long process so I'd suggest watching the video on wave properties he posted on his website that explains the equation thoroughly