## What n1 and n2 represents in the Rydberg Equation?

H-Atom ($E_{n}=-\frac{hR}{n^{2}}$)

Annabella_Amato_1I
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### What n1 and n2 represents in the Rydberg Equation?

In the Rydberg equation, is n1 always the initial and n2 always the final? or is n1 always just the lowest energy value and n2 the highest?

Talia Leano 2H
Posts: 83
Joined: Wed Sep 30, 2020 10:10 pm

### Re: What n1 and n2 represents in the Rydberg Equation?

I'm a little confused by what you mean by n1 and n2 is that in reference to the energy levels n1 and n2? If you are wondering in which order you should use Ninitial and Nfinal though I found this helpful Rydberg Equation image! It is from https://ch301.cm.utexas.edu/section2.ph ... dberg.html
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Connie Liang 3L
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### Re: What n1 and n2 represents in the Rydberg Equation?

Hi! I'm basing the definition of n1 and n2 from the constants and equations sheet we need printed out for the midterm. n1 would be considered the final energy level and n2 would be considered initial energy level.

Jason_Glass_2L
Posts: 89
Joined: Wed Sep 30, 2020 9:43 pm

### Re: What n1 and n2 represents in the Rydberg Equation?

Connie Liang 3L wrote:Hi! I'm basing the definition of n1 and n2 from the constants and equations sheet we need printed out for the midterm. n1 would be considered the final energy level and n2 would be considered initial energy level.

Now I'm kind of confused. I thought N1 is initial and N2 is final because if you derive it out from the E=E(final)-E(initial), you would get v=R * (-1/n(final)^2 + 1/n(initial)^2) which Lavelle rearranges to v=R * (1/n(initial)^2 - 1/n(final)^2). Could someone help me clear this up?

Danielle Goldwirth 3F
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Joined: Wed Sep 30, 2020 10:07 pm

### Re: What n1 and n2 represents in the Rydberg Equation?

Also, just to simplify this discussion as Dr. Lavelle did in his lecture/module, think about calculating temperature differences. If something is 40 degrees Celsius and is now 20 degrees Celsius, then the temperature difference would be T(final) - T(initial = 20 - 40 = - 20 degrees Celsius.
So just remember to do the final value - the initial value and keep track of the n1 and n2 labels representing those values.

Connie Liang 3L
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### Re: What n1 and n2 represents in the Rydberg Equation?

Jason_Glass_3H wrote:
Connie Liang 3L wrote:Hi! I'm basing the definition of n1 and n2 from the constants and equations sheet we need printed out for the midterm. n1 would be considered the final energy level and n2 would be considered initial energy level.

Now I'm kind of confused. I thought N1 is initial and N2 is final because if you derive it out from the E=E(final)-E(initial), you would get v=R * (-1/n(final)^2 + 1/n(initial)^2) which Lavelle rearranges to v=R * (1/n(initial)^2 - 1/n(final)^2). Could someone help me clear this up?

Sorry if my explanation was confusing! Just do final - initial and you'll be good :)

Sarah Huang 3A
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### Re: What n1 and n2 represents in the Rydberg Equation?

Annabella_Amato_1H wrote:In the Rydberg equation, is n1 always the initial and n2 always the final? or is n1 always just the lowest energy value and n2 the highest?

Hi Annabelle! if you are using the frequency is equal to Rydberg's constant((1/(n162)) - (1/(n2^2))), then yes, n1 will always be the initial quantum energy level and n2 will always be the final quantum energy level.

However, if you are using the difference in Energy (which is delta E) is = -((hR/nf^2))-(-((hR/ni^2)), then the nf is the final quantum energy level and the ni is the initial quantum energy level.

These are the two different equations that go with Rydberg's constant, but the first one is for finding the frequency and the second one is to find the energy difference between the two.
I hope that helps!

RaniyaFeroz_1E
Posts: 84
Joined: Wed Sep 30, 2020 9:32 pm

### Re: What n1 and n2 represents in the Rydberg Equation?

Sarah Huang 3A wrote:
Annabella_Amato_1H wrote:In the Rydberg equation, is n1 always the initial and n2 always the final? or is n1 always just the lowest energy value and n2 the highest?

Hi Annabelle! if you are using the frequency is equal to Rydberg's constant((1/(n162)) - (1/(n2^2))), then yes, n1 will always be the initial quantum energy level and n2 will always be the final quantum energy level.

However, if you are using the difference in Energy (which is delta E) is = -((hR/nf^2))-(-((hR/ni^2)), then the nf is the final quantum energy level and the ni is the initial quantum energy level.

These are the two different equations that go with Rydberg's constant, but the first one is for finding the frequency and the second one is to find the energy difference between the two.
I hope that helps!

Wait so both of these are used to calculate different things? I thought the equations were the same and the Planck's constant and rydberg's constant was factored out from the second equation to get the first equation. I think that's what my TA and one of the UAs said.

Ayesha Aslam-Mir 3C
Posts: 112
Joined: Wed Sep 30, 2020 9:43 pm

### Re: What n1 and n2 represents in the Rydberg Equation?

How does the negative sign play into the Ryderg equation? Some formulas are written -R and others with the n1 and n2 switched. I just wanted clarification on whether we could do the calculation either way and just remember to flip the sign? Or at what point would we need to before it influences the true final value of the energy?

Sarah Huang 3A
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### Re: What n1 and n2 represents in the Rydberg Equation?

RaniyaFeroz_2H wrote:
Sarah Huang 3A wrote:
Annabella_Amato_1H wrote:In the Rydberg equation, is n1 always the initial and n2 always the final? or is n1 always just the lowest energy value and n2 the highest?

Hi Annabelle! if you are using the frequency is equal to Rydberg's constant((1/(n162)) - (1/(n2^2))), then yes, n1 will always be the initial quantum energy level and n2 will always be the final quantum energy level.

However, if you are using the difference in Energy (which is delta E) is = -((hR/nf^2))-(-((hR/ni^2)), then the nf is the final quantum energy level and the ni is the initial quantum energy level.

These are the two different equations that go with Rydberg's constant, but the first one is for finding the frequency and the second one is to find the energy difference between the two.
I hope that helps!

Wait so both of these are used to calculate different things? I thought the equations were the same and the Planck's constant and rydberg's constant was factored out from the second equation to get the first equation. I think that's what my TA and one of the UAs said.

You can separate the equations to calculate different things, the frequency is simply derived from the difference from the difference in energy equation. They come from the same equation, but knowing what each of these equations can be used for will make it faster for you to deduce which equation to use during the midterm.