Posted by Sarah on Monday, October 26, 2009 at 4:01pm.
Ionization energy is defined as the minimum energy required to remove an electron from the ground state (n0) to infinity (n∞). Determine the wavelength of radiation required to ionize the hydrogen electron from the n = 2 energy level. Calculate the energy (Joules) associated with this photon. (1 cm1 = 1.986 x 1023 J)
do I use E = RH / n^2 ?
I don't know why I'm given the cm to J conversion, or why they ask for the wavelength first.

Chemistry  DrBob222, Monday, October 26, 2009 at 5:08pm
I would do it the other way around.
delta E = 2.180 x 10^18 J*[(1/n1^2)(1/n2^2)]. With the Balmer series, n1 is 2 and n2 is infinity.
Then delta E = hc/wavelength.
The reason reciprocal cm is given (cm^1) is because wave number = 1/wavelength and many spectroscopists prefer to use wave number instead of wavelength. Also, if you use the Rydberg constant, then
1/wavelength = R[(1/N1^2)  (1/N2^2)] and you don't need to convert to wavelength first to get energy in joules.

Chemistry  Sarah, Monday, October 26, 2009 at 6:01pm
ok so 1/lambda = (2.18e19) (.25  0)
1/lambda = 5.45e19
then i set up a proportion to convert it into joules?
1 cm1/1.986e23 joules = 5.45e19 cm1/x
I got x = 1.082e41 joules and that it so not right..

Chemistry  Sarah, Monday, October 26, 2009 at 9:12pm
thank you i got it now!!
thanks so much for your help!!
Answer This Question
Related Questions
 chem  Ionization energy is defined as the minimum energy required to remove an ...
 Physics  The following values are the only allowable energy levels of a ...
 chemistry  the following values are the only energy levels of a hypothetical ...
 Chemistry  An electron is excited from the n=1 ground state to the n=3 state in...
 Chemistry  Calculate the energy, in joules required to ionize a hydrogen atom ...
 chem  How much energy is required to ionize a hydrogen atom in its ground (or ...
 Chemistry (Follow up post  Dr.BOB22)  Ionization is when an electron is ...
 Physics  What wavelength photon would be required to ionize a hydrogen atom in ...
 chemistry  Calculate the energy required for ionization of electron from the ...
 chemistry  Calculate the energy required for ionization of electron from the ...
More Related Questions