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Homework Help: Helium atom and bohr model

  1. Jul 21, 2012 #1
    1. The problem statement, all variables and given/known data

    He+ ion consists of a nucleus which is an alpha particle plus one orbiting electron.Hence it has a net positive charge.
    a)Derive an expression for the electron state energies
    b)what is the wavelength associated with a transition between the lowest two energy states?

    2. Relevant equations

    3. The attempt at a solution
    For part a) i figured it out to be E=(-4R)/(n^2) where R is the rydbergs constant
    for part b) im having trouble not sure where to begin
  2. jcsd
  3. Jul 21, 2012 #2
    Don't forget, the wavelength of a photon emitted, for a drop in energy level, is proportional to the difference in energies between the two levels.

    I think that will be useful.
  4. Jul 21, 2012 #3
    should i use this

    ΔE = RchZ²{1/n²(1) - 1/n²(2)}

    where R is the Rydberg constant (1.0974 x 10E7 m-¹); c the speed of light in vacuum (2.9979 x 10E8 m s-¹); h Planck's constant (6.626 x 10E-34 J s); Z nuclear charge; n(1) & n(2) are the principal quantum numbers of the electron transition
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