A hydrogen atom emits a photon as its electron changes from n = 7 to n = 2. For the H atom, En = -2.18E-18*(1/n2) J.?

What is the wavelength (in m) of the photon? 

In what region of the electromagnetic spectrum is this photon found? Please enter the full name of the spectral region - infrared, visible (400-700 nm) or ultraviolet.

1 Answer

  • 4 months ago
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    Delta E = -2.18X10^-18 (1/n^2f - 1/n^2i)

    Delta E = -2.18X10^-18 (1/4 - 1/49) = -5.00X10^-19 J/photon

    E = hc/wavelength

    5.00X10^-19 J = 6.626X10^-34 Js (3.00X10^-8 m/s) / wavelength

    wavelength = 3.97X10^-7 m = 397 nm

    region is near ultraviolet (just below 400 nm visible range)

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