Question #2e787

1 Answer
Oct 6, 2017

n_i = 8 ni=8

Explanation:

Your tool of choice here will be the Rydberg equation, which looks like this

1/(lamda) = R * (1/n_f^2 - 1/n_i^2)1λ=R(1n2f1n2i)

Here

  • lamdaλ is the wavelength of the photon
  • RR is the Rydberg constant, equal to 1.097 * 10^(7)1.097107 "m"^(-1)m1
  • n_InI is the initial energy level of the transition
  • n_fnf is the final energy level of the transition

Now, you know that the electron starts on an initial energy level n_ini and ends up on the third energy level, so

n_f = 3nf=3

Moreover, you know that this transition is accompanied by the emission of a photon of wavelength

lamda = 9.54 * 10^(-7)λ=9.54107 "m"m

Rearrange the Rydberg equation to solve for n_ini

1/(lamda) = R * (n_i^2 - n_f^2)/(n_i^2 * n_f^2)1λ=Rn2in2fn2in2f

This is equivalent to

n_i^2 * n_f^2 = lamda * R * n_i^2 - lamda * R * n_f^2n2in2f=λRn2iλRn2f

lamda * R * n_i^2 - n_i^2 * n_f^2 = lamda * R * n_f^2λRn2in2in2f=λRn2f

n_i^2 * (lamda * R - n_f^2) = lamda * R * n_f^2n2i(λRn2f)=λRn2f

Finally, you should end up with

n_i = sqrt( (lamda * R * n_f^2)/(lamda * R - n_f^2))ni= λRn2fλRn2f

Plug in your values to find

n_i = sqrt( (9.54 * color(blue)(cancel(color(black)(10^(-7))))color(red)(cancel(color(black)("m"))) * 1.097 * color(blue)(cancel(color(black)(10^7)))color(red)(cancel(color(black)("m"^(-1)))) * 3^2)/(9.54 * color(blue)(cancel(color(black)(10^(-7))))color(red)(cancel(color(black)("m"))) * 1.097 * color(blue)(cancel(color(black)(10^7)))color(red)(cancel(color(black)("m"^(-1)))) - 3^2))

n_ i = 8.017 ~~ color(darkgreen)(ul(color(black)(8)))

Therefore, you can say that this electron underwent a n_i = 8 -> n_f = 3 transition.