En = -hR / n^2

[Alison Le 2E]

Hi! What exactly is this equation, En = -hR / n^2 used for? I recently was doing a UA worksheet problem and used it on a problem where I was supposed to "Determine the amount of energy in J/mol that would be released this process" (this process referring to the third line of light in the Lyman series), but I got it wrong because I was not supposed to use that equation. Can someone explain why I can't use that equation for this problem? Thanks!

[Hannah Joo 2D]

That formula (En = -hR/n^2) is used to find the energy at a given energy level. To find the energy released, you need to compare let's say the energy at n=1 and n=3. Hope that helps!

[Kailin Mimaki 2K]

You use this equation when you are given the values of n in order to find the amount of energy released when electrons are traveling down to certain energy levels. When there are two energy levels, you subtract the initial amount of energy from the final amount. Hope this helped!

[Brenda Tran 3C]

This equation is used to find the energy of the electron at the given shell (n). You can also use this equation to find n when given the energy value.

[505686385]

For the equation En = -hR / n^2, you will usually start off by being given two values of n which represents electrons jumping from different energy levels. Then you use these n values to find the amount of energy released when electrons are going down to certain energy levels. You would then subtract the initial amount of energy from the final amount to find the energy released. Sometimes the problem will be asking you to find frequency and wavelength. To find frequency from this point, since you now know the energy released, you can divide that number by plank's constant. And from this point, since you know frequency, you can find wavelength by taking the speed of light and diving that by the frequency. Hope this helps!

[Renga Rengappa 1D]

You usually use this equation to find the energy of an electron at a specific sub shell level (n = 1,2,3,…). And you usually would use this to find the change in energy of an electron going from one n level to another, or to even find an n level using the change in energy.