1. WARM UP
1. Write the chemical symbol for a nitrogen isotope that has 11 neutrons.
2. What is the average atomic mass of magnesium if you determine the following data for the isotopes: Mg-24 = amu and 18.05% abundant Mg-26 = amu and 81.95% abundant

2. Wave Mechanics
Chemistry II

3. Waves
Carry energy (and light)

4. Waves frequency (ν) in Hertz (waves/second) wavelength (λ) in nm
Inversely proportional
High ν, low λ

5. Waves
Wave Equation
u = λν (u = speed)
Speed of light (3.00 x 108 m/s)

6. Photoelectric Effect
Light frequencies release metal e-

7. Photoelectric Effect
Light is both a wave and a particle

8. Planck’s Equation E = hν h = Planck’s constant (6.63 x 10-34 J·s)
Energy (in J) of a wave depends on its frequency
E = h x c/λ

9. WRAP UP
Calculate the wavelength of a wave if its frequency is 4.2 x 1014 Hz.
What color is this light wave?

10. WARM UP Use a short sentence to describe each of the following terms:
Wave
Frequency
Wavelength
Energy
Photoelectric effect

11. WRAP UP
Calculate the energy of a wave that has a wavelength of nm.