Bohr Atom Interactive
Bohr Atom Interactive

The Bohr Atom (51.0K)
The Bohr Atom Interactive illustrates the concept of emission and absorption spectra as well as Kirchoffs Laws by having students "Build an Atom." Students can construct an atom with energy levels corresponding to different colors of light. By heating a gas of these atoms or shining a continuum light through them students will construct different spectra.

Neils Bohr realized that the changes in electron orbitals were critical to the spectral line signatures of each element, and were also predictable sequences. Here we will apply his work to spectral identification over a vareity of energies, in and out of the visible spectrum.

 1 H alpha is the bright red emission line we see in the Sun's chromosphere when a total eclipse is about to start, and also the red color of prominences we see hanging above the totally eclipsed Sun. If it is the most common and least energetic of the Balmer series of electron transitions involving n = 2 and higer, it is the change from: Need a Hint? A) n = 2 to n = 1 B) n = 2 to n = 3 C) n = 3 to n = 2 D) n = 4 to n = 2

At the turn of the century, a far sighted Danish physicst first related the spectral lines seen in the stars for almost a century with the electron levels and chemical properties of the elements, showing that the spectra could be used as a chemical fingerprint for the composition of stars.

 2 Who first showed that the electron level structure of atoms was quantified and predictable, and related these changes to the spectral lines created by elements? Need a Hint? A) Albert Einstein B) Earnest Rutherford C) Neils Bohr D) Arthur Compton

Once you become familar with the pattern of orbitals in the Bohr atom, predictions of spectral features can be made.

 3 Given that red hydrogen alpha is the emission line from third to second level, and greenish hydrogen beta is the four to two drop, describe hydrogen gamma. Need a Hint? A) orange emission from n = 4 to n = 1 B) blue absorption at n = 4 to n = 3. C) Violet emission at n = 5 to n = 2. D) Ultraviolet at n = 6 to n = 1.

Notable as the Balmer lines are visually, many more electrons are involved in the transitions to and from n = 1, the ground state. But these Lyman series changes are too energetic for us to see visually.

 4 Why did the latest spectrograph for the Hubble SPace telescope carry detectors for the Lyman lines, but no telescope on the ground is so equipped? Need a Hint? A) The Hubble always gets the good stuff first. B) These energies lie in the ultraviolet, and the HST orbits above the absorbing ozone layer. C) These longer waves are absorbed at ground level by greenhouse gases like carbon dioxide and water vapor. D) Only in space can these detectors function.

The Spitzer Space Telescope is the infrared version of the Hubble, and made to map the warm regions giving off heat less energetic than the visible Balmer lines.

 5 Which of these types of lines would the Spitzer concentrate on studying? Need a Hint? A) The Lyman series of lines, going down to n = 1 B) The Balmer series of lines, going down to n = 2. C) The Paschen series of lines, going down to n = 3. D) The ionization lines of escaped electrons.