1. Wavelength, Frequency, & Energy of Light
Byno Chemistry 2013

2. Discuss in your group Why does Aluminum not burn?
Why does Alcohol burn but it will not react with anything else?
Why does Aluminum react with Hydrochloric Acid?
Why does Calcium Carbonate react with vinegar, but it doesn’t burn?

3. I can . . .
Identify and use the symbols for frequency and speed of light
Use 3x108 m/s as the value for the speed of light
Calculate E = hv using Planck’s constant
Calculate c = λv using the speed of light

4. Symbols Symbol Meaning Value or Unit c Speed of light 3x108 m/s h
Planck’s constant
6.63 x Js E
Energy
Joules (J) ν
frequency
Hertz (Hz) λ
wavelength
Nanometer (nm)

5. Visible Light
Visible light breaks into a spectrum of colors depending on the wavelength of the light

6. Spectroscope
A spectroscope is a device used to separate the colors of visible light and measure their wavelengths

7. Electron Energy Levels
Electrons exist in the electron cloud but they can be found in distinct ‘levels’
They are the s-orbital, p-orbital, d-orbital, and f-orbital
Electrons can jump up from one orbital to the next when energy is applied to the atom

8. Ex. Cadmium

9. S-Orbital
Groups 1 and 2, and Helium

10. P-orbital
Groups (except Helium)

11. D-orbital
Transition metals – Groups 3-12

12. F-orbital
Lanthinide and Actinide series – Rare Earth Metals

13. Electrons
The motion of electrons in the electron cloud of an atom creates low energy waves such as visible light and radio waves
The energy is the result of electrons hopping from one level up to the next
Energy is emitted when the electron falls back to the original level

14. Reactivity
An element can react with another element if it has electrons that can move
When a chemical substance reacts with another, the electrons move and give off energy in the form of light

15. Wavelength
The energy of the electron’s movement in a chemical reaction can be calculated
Speed of light (m/s)
Wavelength
(m)
Frequency (Hz)
Example: A helium laser emits light with a wavelength of 633 nm. What is the frequency of the light?

16. Energy
Now that we know the wavelength, we can calculate the energy of the electron
Energy
(J)
Frequency
(Hz)
h (Planck’s Constant)
6.63 x Js
Example: A helium laser emits light with a wavelength of 633 nm. What is the energy of its electrons?
We previously calculated frequency = 6.00 Hz

17. Practice
What is the energy of light whose wavelength is 4.06 x m?
c÷λ = ν
ν = 3.8x108 m/s ÷ 4.06x10-11 m
ν = 7.39x1018 Hz
E = h × ν
E = 6.63x10-34 Js × 7.39x1018 Hz
E = 4.9x10-15 J