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Wavelength, emission spectrum, electron transitions

  • Thread starter FsLiu
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  • #1
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Homework Statement



Determine the wavelength (in nm, to one decimal place) of the line in the emission spectrum of the He+ ion produced by a transition from n = 3 to n = 1.

Homework Equations


I used the Rydberg equation for this, although I'm not sure it is the correct one to use.
fa7bd92080914c973a88453a20c0c730.png



The Attempt at a Solution


Plugging in n1=1 and n2=3, I get an answer of 102.6nm. A search on wikipedia for the Lyman series also shows that transition from n=3 to n=1 is 102.6nm.

The solution given, however, is 25.6nm. Obviously I am not understanding the question. Help would be appreciated.
 

Answers and Replies

  • #2
Ygggdrasil
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The Rydberg constant will be different for He+ than for hydrogen because He+ has more protons in its nucleus.
 
  • #3
phyzguy
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The equation you used is for Hydrogen. The He ion has a charge of +2, so the Rydberg constant is modified. Go back and look up the equation for how this Rydberg constant is derived.
 

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