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    Can someone help me with this? I have way too much homework I don't understand. Any way you can help me is fine. Thanks.

    The Bohr model for single electron atoms predicts that the energies of the allowed orbitals are given by: En = (-2.178 * 10^-18) * Zsquared / n squared where n = 1, 2, 3...... and Z is the nuclear charge

    i) calculate the minimum energy (in J) required to ionise a ground state hydrogen atom

    ii) calculate the wavelength (in nanometres) of the photon emitted by an electron in making the transition from the n=2 to n=1 levels of the single electron ion, He+.

    The formula for hydrogenic atom is fixed, E = - 13.6/n^2 eV

    Change in E(in Joule) = difference between E at n = 1 and n =2 = hf = hc/wavelength

    1 ev is roughly 1.6 x 10^-19 J (do the conversion right, you should be able to get the correct answer).
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Updated: November 8, 2008

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