Chemistry
posted by Priscilla .
Calculate the level from which the electron fell, n2, for the hydrogen line you observed.
wavelength (lambda) = 400 nm
n1 = 2
RH = 2.18 x 10^18
I keep having trouble with finding n2. Is the above given right to plug in for 1/(lambda) = RH (1/n1^2  n2^2)
thank you for any help

no. Your constant is not right.
The Rydberg constant, R_{H} = 1.097E7.
1/wavelenth = RH(1/n1^2  1/n2^2)
wavelength must be converted to meters. 
Okay, I was solving out this this equation for n2^2
n2^2 = 1(1/n  E/Rh)
Is this right? 
If its okay, can you show me in detail how to find n2^2 because I have done this three times and I'm still a little confused by this.

I think it is far easier to substitute the numbers, then do the math than try to manipulate all of the variables. I use one of the following where w = wavelength:
1/w = 2.180E19/hc x (1/n1^2  1/n2^2) but it is much easier to simplify that by
1/w = R_{H}(1/n1^2  1/n2^2). That formula is the original Rydberg formula I believe. Using the 2.180 number as well as substituting h and c is just asking for more places for a mistake in my opinion. 
ok thank you very much