1. Bohr Model Of Atom

2. Spectrum • Continuous spectrum is the rainbow of colors containing all wavelengths • Line spectrum contains only certain colors or wavelengths • When gases are given energy, they emit line spectra which are characteristic of that gas

3. Continuous Spectrum • Line Spectrum of Hydrogen

4. Niels Bohr • Said electrons occupy the atoms in quantized energy levels • Each level (orbit) is assigned an integer (n) called the principal quantum number • As n increases, the radius of orbit is greater

5. Energy • Energy of the electron depends on the level it occupies En = - RH ( 1/n2) RH is called the Rydberg constant RH = 2.18x10-18 J

6. Coulomb’s Law • The energy comes from the potential energy resulting from a separation between a positive and negative charge • Coulomb’s law describes this q1 and q2 are the two charges r is the distance between the charges k = 2.31 x 10-19

7. When electrons occupy the lowest possible energy level, they are in ground state • When in higher levels, they are in excited state

8. Hydrogen Line Spectrum • H atom absorb a quantum of energy • Energized electron “jumps” to a higher level • When it falls back down, it gives off energy as a photon of light • The frequency of the light depends on the levels it falls from and to

9. Equation ΔE = Ef – Ei hν = RH ( 1/nf2 - 1/ni2) frequency of light given off depends on the level transition

10. Example 1 • Calculate the frequency and wavelength of light given off when an electron in a H atom falls from n=4 to n=2. What color is it?

12. Ionization of Energy • Energy that would be needed to completely remove the electron; make it go from n = 1 to n = ∞

13. Example 2 • Calculate the energy required to ionize an electron from the ground state.