Skip to main content
Submitted by goosegirl13 on Sat, 02/20/2010 - 01:18

Well, the real subject title should be: determining the wavelength and color of radiation emitted when an atom of X undergoes a transition from lowest excited state to the ground state.

Alrighty... What do we know? The energy needed to ionize an atom of element X when it is in its ground stat is 500 KJ/mol.
The energy needed to ionize an atom of element X in its lowest excited state is only 120 KJ/mol.

How do we find the wavelength?

I considered using Rydberg's equation to determine the wavelength but the equation only works for hydrogen. :( I'm really lost. Please help!

goosegirl13 wrote:

Well, the real subject title should be: determining the wavelength and color of radiation emitted when an atom of X undergoes a transition from lowest excited state to the ground state.

Alrighty... What do we know? The energy needed to ionize an atom of element X when it is in its ground stat is 500 KJ/mol.
The energy needed to ionize an atom of element X in its lowest excited state is only 120 KJ/mol.

How do we find the wavelength?

I considered using Rydberg's equation to determine the wavelength but the equation only works for hydrogen. :( I'm really lost. Please help!

If you sketch out the two energy level between ground state and the excited state, you'd find that the energy separation between them is 500 - 120 = 380 kJ/mol
But since you are dealing with an atom, so you'd need to divide this number by the avogadro's constant.

Then when dealing with spectroscopy question, always remember delta E = hf = hc/lambda
f is frequency of the radiation, and with simple manipulation, you get the second eqn, lambda is the wavelength of the radiation, that is what you want to find.

Submitted by shengoc on Sat, 02/20/2010 - 06:54 Permalink