Consider a transition of the electron in the hydrogen atom from \(n=8\) to \(n=3\). (a) Is \(\Delta E\) for this process positive or negative? (b) Determine the wavelength of light that is associated with this transition. Will the light be absorbed or emitted? (c) In which portion of the electromagnetic spectrum is the light in part (b)?

Short Answer

Expert verified
(a) ΔE is negative. (b) The wavelength of light is 957.3 nm and is emitted. (c) The light is in the infrared portion of the electromagnetic spectrum.

Step by step solution

01

Calculate the energy of the initial and final levels

We use the formula for the energy of an electron in the nth energy level of a hydrogen atom: \[E_n = - \frac{13.6 eV}{n^2}\] For the initial level (n=8): \[E_{initial} = - \frac{13.6 eV}{8^2} = -\frac{13.6 eV}{64} = -0.2125 eV\] For the final level (n=3): \[E_{final} = - \frac{13.6 eV}{3^2} = -\frac{13.6 eV}{9} = -1.511 eV\]
02

Calculate the change in energy, ΔE

The change in energy during the transition is given as: \[\Delta E = E_{final} - E_{initial}\] \[\Delta E = -1.511 eV - (-0.2125 eV) = -1.511 eV + 0.2125 eV = -1.2985 eV\] Since ΔE is negative, that means energy is released during the transition.
03

Calculate the wavelength associated with the change in energy

To calculate the wavelength of light associated with the transition, we use the energy-wavelength formula: \[\Delta E = \frac{hc}{\lambda}\] Where h is Planck's constant (h = 4.1357 × 10⁻¹⁵ eV·s), c is the speed of light (c = 2.998 × 10⁸ m/s), and λ is the wavelength. Solving for the wavelength: \[\lambda = \frac{hc}{\Delta E}\] Now we plug in the numbers: \[\lambda = \frac{(4.1357 × 10^{-15} eV·s)(2.998 × 10^8 m/s)}{-1.2985 eV} = 9.573 × 10^{-8} m = 957.3 nm\]
04

Determine if the light is absorbed or emitted

Since ΔE is negative and energy was released during the transition, the light associated with this transition must be emitted.
05

Identify the portion of the electromagnetic spectrum

The wavelength of the light emitted (957.3 nm) falls in the infrared (IR) portion of the electromagnetic spectrum, which typically has wavelengths between 700 nm and 1 mm. Final answers: (a) The change in energy, ΔE, is negative. (b) The wavelength of light associated with this transition is 957.3 nm, and the light is emitted. (c) The light is in the infrared (IR) portion of the electromagnetic spectrum.

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