2. Problems with Rutherford’s Model Why do elements produce spectral lines instead of a continuous spectrum? And Why aren’t the negative electrons pulled into the nucleus causing the atom to collapse?

3. Electrons as Waves Properties of Waves –Wavelength – ( ) the distance between peaks –usually given in nanometers (nm) –Amplitude - (A) maximum displacement from zero

4. Electrons as Waves Frequency – ( ) the number of waves that pass a point per unit time Cycles /second = 1 Hertz (Hz) What happens to the wavelength as the frequency changes?

5. Electrons as Waves As decreases, increases How does the energy of the wave change as the frequency increases?

6. Electromagnetic Spectrum All waves that travel at the speed of light are included in the Electromagnetic Spectrum c = x c = speed of light = 3.00 x 10 8 m/s E = h = hcE = energy h = Planck's constant = 3.363 x 10 -34

7. Visible Light Which color has the greatest ? Red Which color has the greatest ? Violet Which color has the greatest E? Violet

8. Visible Light Continuous spectrum – emission of all wavelength of visible light Emission Spectrum (bright line spectrum) – the specific set of wavelengths of light emitted from a particular element

9. Visible Light Continuous Spectrum Examples: Sunlight, incandescent light Emission spectrum examples: energized elements and compounds

10. -Bohr explained hydrogen's emission spectrum with quantized orbits. - Every element produces a different bright line spectrum due to a different arrangement of electrons

11. Bohr’s Model of the Atom  The atom can only absorb and emit specific amounts of energy equal to the difference between orbitals.  The orbits are quantized and electrons can only exist in whole number orbits.  Electrons can never be between orbits.

12. Bohr’s Model With these conditions Bohr was able to explain the stability of atoms as well as the emission spectrum of hydrogen. According to Bohr's model only certain orbits were allowed which means only certain energies are possible. These energies naturally lead to the explanation of the hydrogen atom spectrum.