1. The Bohr Model of the Atom

2. Kirchoff and Robert Bunsen (1854)
Observed that light was given off when they heated different chemicals in their designed burner
They passed the light through a prism and saw separate lines instead of a continuous spectrum.

3. Absorption and Emission Spectra
Emission spectra- the colors produced by an object when burned or heated.
Absorption spectra- the colors that are not shown, rather absorbed in the spectrum

4. 7.3 Hydrogen Spectrum Only four lines are emitted:
Red, green, blue, violet
Only certain energies are allowed.

5. Why do elements produce these lines?
To understand emission spectrum, we must understand these two terms:
Ground state: the lowest energy state for the electron
Excited state: state where electron has higher energy than ground state.

6. Why do elements produce these lines?
Atoms are heated, which adds energy. The electron become excited (thus unstable). They want to return to their normal, or ground state. To do so, they give off energy in the form of EMR.

7. Scientists associated with the H spectrum
Balmer: developed a numerical relationship between the wavelength of the lines in the spectrum and the amount of energy
Lyman: discovered lines produced in the UV range.
Paschen: discovered lines produced in the IR range

8. Electron transitions involve jumps of definite amounts of energy.
This produces bands of light with definite wavelengths.

9. 7.4 The Bohr Model
The electron orbits the nucleus in fixed paths called orbits (like the planets orbit the sun).
The electron can jump to higher orbitals when energy is added.
The electron’s energy can be calculated in the different orbits.
People sometimes call my model of the atom the Planetary Model!

10. Bohr Model of the Atom How does this relate to the Hydrogen spectrum?
Bohr calculated the energy that the electron would lose as it fell from higher orbits to lower orbits.
Bohr’s calculations agreed exactly with Lyman, Balmer and Paschen’s observations.

11. Bohr Model of the Atom Bohr Model of the Atom
Bohr’s model worked very well for the Hydrogen atom.
Through Bohr’s work, as well as the other scientists mentioned, a very good understanding of the electron within the atom was now in place.

12. Downfalls to Bohr’s Model
Downfalls to Bohr’s Model of the Atom
Downfalls to Bohr’s Model
1. Bohr’s model of the atom worked very well for the hydrogen atom and the He+, but failed when applied to multielectron atoms.
2. Bohr’s model could not explain why the electron could not exist between orbits.