Exploring Bohr's Model: Understanding Electron Emission in Hydrogen Atoms

[shanktank]

hi all,
quick question with regards to bohr's model

From what energy level did an electron fall if it emits a photon of 9.38 x 10^-8 wavelength when it reaches fround state within a hydrogen atom?


this is a textbook question so i know the answer is n = 6


attached is a copy of my work, please let me know where I'm going wrong.

 

[Doc Al]

You are mixing up n_i and n_f. n_f is the final level, which in this case is the ground state (what does n_f equal?). n_i, the initial level, is what you are trying to find.

 

[shanktank]

oh ok umm is there anywhere that i should know what n_f does equal. does the hydrogen part give a clue or ?

 

[Doc Al]

Ground state is the clue! What's the number of the lowest energy level in the Bohr model?

 

[Doc Al]

From what energy level did an electron fall if it emits a photon of 9.38 x 10^-8 wavelength when it reaches fround state within a hydrogen atom?

I assume that should have said "when it reaches the ground state". Right?

 

[shanktank]

ok here's where I'm not as of now. did i make an error in one or more of the steps?

 

[Doc Al]

Yes, you made an error. n_f is an integer, not an energy. What's the orbital number of the lowest energy orbit? (Open the book! )

 

[shanktank]

its not 1?

 

[shanktank]

In atoms with a single electron (essentially the hydrogen atom), the energy of an orbital (and, consequently, of any electrons in the orbital) is determined exclusively by n. The n = 1 orbital has the lowest possible energy in the atom.
from wikipedia

 

[Doc Al]

its not 1?

Of course it is.

I hope you have a textbook to use and not just Wiki.

 

[shanktank]

well replacing that into the equation i have i still get a way off answer?

 

[shanktank]

oh nevermind! awesome thankyou so much for the help Doc