Rydberg equation [ENDORSED]
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Re: Rydberg equation [ENDORSED]
In class I will cover this topic in detail using more fundamental concepts to solve problems (and not directly using the Rydberg equation).

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Re: Rydberg equation
The Rydberg equation is used in to find the wavelength of light emitted when an electron moves between energy levels. This one of the concepts covered under the quantum mechanics of the atom.

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Re: Rydberg equation
The Rydberg formula, by definition, is a mathematical formula which predicts the wavelength of light coming from an electron moving between energy levels of an atom according to the science website, ThoughtCo.

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Re: Rydberg equation
KHowe_1B wrote:What exactly is the Rydberg equation and how do you know when to use it?
You usually use igt in place of a constant when trying to calculate wavelength or frequency!

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Re: Rydberg equation
Jessa Maheras 4F wrote:The Rydberg equation is used in to find the wavelength of light emitted when an electron moves between energy levels. This one of the concepts covered under the quantum mechanics of the atom.
is the equation just for when an electron is moving from a higher energy level to a lower energy level, thus finding the frequency of a photon that is emitted? or can it also be used for when an electron is moving from a lower energy level to a higher energy level, (finding the frequency of a photon that is absorbed)? is absorbed even the correct term?

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Re: Rydberg equation
to clarify, is this the speed of light= frequency * wavelength equation? if so it would be used to determine the value of one of those if given the other two.

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Re: Rydberg equation
that's a different equation. the rydberg equation can be used to calculate wavelength or frequency of an electron when it moves to a different energy level

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Re: Rydberg equation
The rydberg equation, if i am correct, is derived from Bohr's equation. Dr. Lavelle prefers to use Bohr's over the Rydberg equation though.

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Re: Rydberg equation
Rydberg equation states that the energy of energy levels equals to hR/n^2 (n=1,2,3...), h is planck constant(6.63*10^34 Js), R is Rydberg constant (3.29*10^15 Hz)

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Re: Rydberg equation
You would use the Rydberg equation to calculate the wavelength of light when an electron moves energy levels.
Re: Rydberg equation
The Rydberg formula is a mathematical formula used to predict the wavelength of light resulting from an electron moving between energy levels of an atom. Rydberg's findings were combined with Bohr's model in which he found 1/λ = RZ2(1/n12  1/n22) where:
λ is the wavelength of the photon (wavenumber = 1/wavelength)
R = Rydberg's constant (1.0973731568539(55) x 107 m1)
Z = atomic number of the atom
n1 and n2 are integers where n2 > n1.
Here's a video that explains it a little more in depth: https://www.youtube.com/watch?v=4kOdbqoycmY
λ is the wavelength of the photon (wavenumber = 1/wavelength)
R = Rydberg's constant (1.0973731568539(55) x 107 m1)
Z = atomic number of the atom
n1 and n2 are integers where n2 > n1.
Here's a video that explains it a little more in depth: https://www.youtube.com/watch?v=4kOdbqoycmY

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Re: Rydberg equation
In class, Professor Lavelle wrote the Rydberg equation with a negative sign on the right to show that energy was being lost. Unfortunately when I used the equation that way, my negatives got all messed up and my answer was wrong...Should I just forget that negative?

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Re: Rydberg equation
Can someone clarify why the Rydberg equation is always negative? Because you're "losing" energy because it's being transferred somewhere else?

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Re: Rydberg equation
erica thompson 4I wrote:Can someone clarify why the Rydberg equation is always negative? Because you're "losing" energy because it's being transferred somewhere else?
The Rydberg equation is negative because it is comparing the energy difference between the two levels the electrons transitioned between. When an electron transitions from a higher energy level to a lower one, it loses energy which explains the negative sign.

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Re: Rydberg equation
erica thompson 4I wrote:Can someone clarify why the Rydberg equation is always negative? Because you're "losing" energy because it's being transferred somewhere else?
The Rydberg equation is negative because it is comparing the energy difference between the two levels the electrons transitioned between. When an electron transitions from a higher energy level to a lower one, it loses energy which explains the negative sign.

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Re: Rydberg equation
rachel liu 3k wrote:In class, Professor Lavelle wrote the Rydberg equation with a negative sign on the right to show that energy was being lost. Unfortunately when I used the equation that way, my negatives got all messed up and my answer was wrong...Should I just forget that negative?
When using the Rydberg formula, the order of your two principal quantum numbers (the two n's that represent the energy levels between which the electron is traveling) is very important. The equation the formula Lavelle wrote on the board (with a negative sign) places the final principal quantum number before the initial, which is, in a way, quite intuitive because many chemistry formulas contain this motif of final minus initial. By contrast, the formula posted by MAC 1A above (without the negative sign) places the initial principal before the final, essentially distributing the negative sign. This confusing detail is likely the main reason Lavelle encouraged us to use the difference of two Bohr equations rather than the plugandchug Rydberg formula.
Re: Rydberg equation
Can someone please tell me which units cancel out when solving the Rydberg equation?

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Re: Rydberg equation
melinak1 wrote:are the final units wirtten in Hz or Js?
This depends on what the question is asking for. The traditional form of the Rydberg formula, as posted by MAC 1G above, allows you to plug in constants on the left side to get 1 over the wavelength of the photon that will be emitted/absorbed when an electron transitions between the energy levels represented by your principal quantum numbers. If the problem you are attempting to solve only asks for the wavelength, you can simply take the reciprocal of whatever you get on the right side to get an answer in m (which you would then most likely convert to nm for convenience). On the other hand, a more complicated problem could ask for the frequency of the emitted light or even the energy of the photon. In those cases, you would use and/or as needed, and your final answer would be in Hz or Joules, respectively.
Last edited by Sean Cheah 3B on Sat Oct 12, 2019 12:33 pm, edited 1 time in total.

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Re: Rydberg equation
Megan_1F wrote:Can someone please tell me which units cancel out when solving the Rydberg equation?
The principal quantum numbers (the n's) have no units. The Rydberg constant has the units . Basically, everything on the right side will work out to some answer with the units . This matches the left side as 1 over the frequency would naturally also have the units . There's really no cancelling of units happening at all in this formula AFAIK.

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Re: Rydberg equation
The rydberg equation I think is just an equation that combines a few steps of the Einitial  Efinal method.

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Re: Rydberg equation
MAC 1G wrote:The Rydberg formula is a mathematical formula used to predict the wavelength of light resulting from an electron moving between energy levels of an atom. Rydberg's findings were combined with Bohr's model in which he found 1/λ = RZ2(1/n12  1/n22) where:
λ is the wavelength of the photon (wavenumber = 1/wavelength)
R = Rydberg's constant (1.0973731568539(55) x 107 m1)
Z = atomic number of the atom
n1 and n2 are integers where n2 > n1.
Here's a video that explains it a little more in depth: https://www.youtube.com/watch?v=4kOdbqoycmY
Thank you for this! I'll definitely check this video out.

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Re: Rydberg equation
You use the Rydberg equation to calculate the wavelength of light released when an electron jumps down to lower energy levels.

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Re: Rydberg equation
What does the Energy value that we calculate in the Rydberg's Equation represent? The energy of the emitted EMR? or the energy (gained or lost) of the electron as it is moving between discreet energy levels? Or is it the same?

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Re: Rydberg equation
Tauhid Islam 1F wrote:What does the Energy value that we calculate in the Rydberg's Equation represent? The energy of the emitted EMR? or the energy (gained or lost) of the electron as it is moving between discreet energy levels? Or is it the same?
I believe the energy value calculated in the Rydberg's Equation represents the energy of the electron at a specific energy level. To find the energy gained or lost of the electron as it moves between quantum levels, you use the Rydberg Equation to find the energy of the electron at the initial quantum level and then the energy of the electron at the final quantum level. Then, you simply find the change in E = E(initial)  E (final).

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Re: Rydberg equation
Emma Joy Schaetz 1E wrote:Can someone help me understand why we use the Rydberg equation?
The Rydberg equation is used to calculate the energy of an electron at a certain principle quantum level of an atom. We'll usually use it in problems where we're asked to calculate the change in energy, frequency, or velocity that occurs when an electron moves from on quantum level to another. For the example Lavelle showed in class,
"ex. Calculate the frequency of light emitted by a hydrogen atom when an electron makes a transition from the fourth to the second principle quantum level"
we used the Rydberg equation to calculate first the change in energy from the electron moving from the fourth to the second principle quantum level before using the equation E=hv to calculate the frequency of light emitted when this transition occurred.
[E= (hR)/(n^2), n =4]  [E= (hR)/(n^2), n = 2] = change in energy of the electron

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Re: Rydberg equation
The Rydberg equation is found in our textbook and is used to calculate the wavelength of any spectral line in many chemical elements. However, Dr. Lavelle taught us a different approach in class because the Rydberg equation does not really show us why everything is solved the way it is.

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Re: Rydberg equation
The rydberg constant is 3.29x10^15 hz when solving for frequency while in other equations it appears as 1.097x10^7m in other equations. It's important to use the right version of the constant depending on what you are solving for.

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Re: Rydberg equation
The Rydberg equation represents the frequency associated with an electron moving from one energy level to another. The frequency is equal to the Rydberg constant multiplied by the inverse of the final minus initial energy levels. You can use the equation when trying to find the frequency of the wavelength associated with the change in energy levels of the electron.
Re: Rydberg equation
KHowe_1B wrote:What exactly is the Rydberg equation and how do you know when to use it?
Dr. Lavelle said he does not expect us to memorize the Rydberg equation since it is such a shortcut, but would rather us understand the steps to how the equation was made in the first place to solve problems.

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Re: Rydberg equation
The final units of your answer depend on what you are solving for. The principal energy levels (n1 and n2) do not have units. However, if you are solving for the wavelength using the Rydberg equation, the final units of your answer must be meters (or some other measurement of length). For reference, the Rydberg constant in the equation has units m^1.

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Re: Rydberg equation
The Rydberg equation is used to find the wavelength of light as it is absorbed or emitted, and electrons move between energy levels.

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Re: Rydberg equation
If we are given a problem where we must calculate ΔE using empirical equation for a hydrogen atom, must we memorize Rydberg’s constant or can we determine the answer by other means?

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Re: Rydberg equation
The Rydberg equation is 1/λ = RZ2(1/n1^2  1/n2^2), with R=Rydberg constant and Z=atomic number of the atom. This is used to find the light's wavelength of an electron moving through different energy levels.

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Re: Rydberg equation
Ruth Glauber 3L wrote:Where does the name Rydberg come from?
It's named after the Swedish scientist Johannes Rydberg.

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Re: Rydberg equation
Are all of these equations meant to be memorized, or will they be provided on tests?

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Re: Rydberg equation
chrischyu4a wrote:erica thompson 4I wrote:Can someone clarify why the Rydberg equation is always negative? Because you're "losing" energy because it's being transferred somewhere else?
The Rydberg equation is negative because it is comparing the energy difference between the two levels the electrons transitioned between. When an electron transitions from a higher energy level to a lower one, it loses energy which explains the negative sign.
what about when an electron transitions from a lower to higher on? Would energy be positive because energy is being absorbed to advance levels?

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Re: Rydberg equation
KHowe_1B wrote:What exactly is the Rydberg equation and how do you know when to use it?
From what I can tell you will mostly use it whenever frequency is involved in the problem.
Re: Rydberg equation
You can use the Rydberg's formula to when you want to calculate the wavelength of radiation when it transitions from different shell levels.
Re: Rydberg equation
erica thompson 4I wrote:Can someone clarify why the Rydberg equation is always negative? Because you're "losing" energy because it's being transferred somewhere else?
The Rydberg equation is negative because it is looking at the change in energy when you go from a high state to a lower state. If you are going from energy in state 4 to energy in state 2, the energy in state 2 is going to be negative in reference to the energy in state 4.

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Re: Rydberg equation
TimVintsDis3C wrote:Are all of these equations meant to be memorized, or will they be provided on tests?
Most equations are on the reference sheet on the test. That being said it does not hurt to memorize or at least be very familiar with them.

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Re: Rydberg equation
Do we need to understand how the Rydberg equation for other 1electron ions, [(Z^2)hR]/n^2 is derived, or can we just apply it?

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Re: Rydberg equation
i understand why the first equation prof. lavelle showed us is negative (hR/n^2). when he derived the second equation (R[1/n1^21/n2^2]) he kept the negative in front but my TA showed that equation as positive. Which is correct?
Re: Rydberg equation
is there different ways to write the Rydberg equation ? if so which is the most used one

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Re: Rydberg equation
In what kinds of scenarios or questions would we need to use the Rydberg equation?
Re: Rydberg equation
I have seen different equations for solving problems about electrons moving to different energy levels using the Rydberg equation and I was wondering what is the correct value of R?
Re: Rydberg equation
Lizette Noriega 1H wrote:In what kinds of scenarios or questions would we need to use the Rydberg equation?
You use the Rydberg equation in scenarios where electrons are moving to different energy levels, or for solving the amount of energy is present on an energy level. Both scenarios are different equations using the R unit.

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Re: Rydberg equation
KHowe_1B wrote:What exactly is the Rydberg equation and how do you know when to use it?
used to measure the wavelength of light emited when an electron moves from one energy level to the next. Energy of the electron changes when it jumps levels so this equation accounts for that.

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Re: Rydberg equation
ShreyaKannan1B wrote:Is there any problem where you would use Rydberg with another equation?
from my understanding, you would only use the Rydberg EQ when you are looking for the change in energy when an electron moves from one energy level to another.

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Re: Rydberg equation
TimVintsDis3C wrote:Are all of these equations meant to be memorized, or will they be provided on tests?
Rydberg's constant is provided, but the eqn isn't. However, I think you can use E(lowercase n) = hR/n^2 which is on the constants sheet.

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Re: Rydberg equation
Equations will be given on any test. Although the traditional Rydberg equation may not be, but Dr. Lavelle’s preferred Rydberg equ is.

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Re: Rydberg equation
For anyone confused about how the negative sign comes into play, you basically use the Rydberg equation to do Efinal  Einitial. So if an electron was going from n=1 to n=3, you'd do: hR/9  hR/1
This would become positive, which makes sense because the electron is gaining energy.
This would become positive, which makes sense because the electron is gaining energy.

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Re: Rydberg equation
I would just watch the video module on our class website for this. It is about 1 hr long but super helpful in understanding how to do the calculations and understanding of the concept as well.

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Re: Rydberg equation
Since there are different Rydberg equations, does it matter which equation is used or do you have to use a certain one?

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Re: Rydberg equation
I don't think it really matters so long as you get the right answer, but I think Dr. Lavelle prefers that we use the one he taught in class because it allows us to conceptually understand what's occurring. Using his equation might also guarantee partial credit if you get part of the problem wrong, but I'd use whatever equation you're most comfortable using.

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Re: Rydberg equation
I don't think it really matters so long as you get the right answer, but I think Dr. Lavelle prefers that we use the one he taught in class because it allows us to conceptually understand what's occurring. Using his equation might also guarantee partial credit if you get part of the problem wrong, but I'd use whatever equation you're most comfortable using.
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