1. Oct 26, 2006

GLprincess02

The energy (in joules) of an electron energy level in the Bohr atom is given by the expression: $$E_{n}$$= -2.179 x $$10^-18/n^2 J$$where n is the principal quantum number for the energy level. What is the frequency in Hz of the electromagnetic radiation absorbed when an electron is raised up from level with n = 4 to that with n = 9?

I'm unsure of the the formula to use, or even the first step. Any ideas??

2. Oct 26, 2006

marcusl

First use your formula to calculate the energy difference between the two levels. Second, relate that to frequency. Look in your book for the formula giving energy of a photon (hint: it involves Planck's constant). You can show us what you get if you still have questions.

3. Oct 26, 2006

use the equation $$\Delta E = R_{H}^{*} (\frac{1}{n_{f}^{2}} - \frac{1}{n_{i}^{2}}) = hv$$

4. Oct 26, 2006

GLprincess02

Ok, so I plugged both of the numbers (4 and 9) into the equation. Then I subtracted answer #1 from answer #2. Then I divided this number by h (6.626E-34). Am I doing this correctly?

5. Oct 26, 2006

marcusl

Yes, exactly.

6. Oct 27, 2006

ultranet

this is great!, I could learn something here....

7. Oct 27, 2006

GLprincess02

Great I got the answer, thanks for all the help!