2. Electromagnetic radiation
- a form of energy that has wavelike properties
- all forms found in the electromagnetic spectrum
Examples of electromagnetic radiation:
Xrays
Microwaves
Light waves
Radio waves – when you hear static on the radio when you aren’t getting a signal, that is the leftover microwaves from the big bang 15 billion years ago (it is cooling off so now the waves are the energy and wavelength of radio waves)

4. WAVELENGTH AND FREQUENCY ARE TWO IMPORTANT PROPERTIES OF WAVES.
DIFFERENT FORMS OF EMR TRAVEL IN WAVES.
WAVELENGTH AND FREQUENCY ARE TWO IMPORTANT PROPERTIES OF WAVES.

5. Wave Characteristics Amplitude Wavelength Wavelength
2 sec
0 sec
Amplitude
Wavelength
Wavelength
Frequency
Amplitude
The shortest distance between two equivalent
Points (meters)
How many waves pass a certain point per sec. (s-1 OR Hz)
Wavelength – the shortest distance between two equivalent points on a wave
Frequency – how many wave pass a certain point per second
Amplitidude –the height of the wave from crest to origin
State: Light travels as photons; photons have no mass but have energy
The energy a photon has is based on the equation E = hv
Energy is directly proportional to the frequency. Frequency has a unit of Hz which is = 1 𝑠 or s-1 or per second.
Wavelength is also related to frequency; how many people know the speed of light? Yes, what is it? EA 3 x 108 m/s
The speed of light is a constant that is known. Speed of light is based on the speed it travels over time. Wavelength is in meters and frequency is per second, so c=vλ
The height of a wave from crest to origin

6. THE HIGHER THE FREQUENCY, THE SHORTER THE WAVELENGTH
FREQUENCY = THE NUMBER OF WAVES THAT PASS BY A FIXED POINT PER SECOND.
THE HIGHER THE FREQUENCY, THE
SHORTER THE WAVELENGTH

7. THE HIGHER THE FREQUENCY, THE HIGHER THE ENERGY
FREQUENCY = THE NUMBER OF WAVES THAT PASS BY A FIXED POINT PER SECOND.
THE HIGHER THE FREQUENCY, THE HIGHER THE ENERGY

8. THE HIGHER THE ENERGY, THE SHORTER (SMALLER) THE WAVELENGTH

9. Practice

10. Photons - released during electromagnetic radiation
– tiny particles that have no resting mass which carry a quantum of energy
All photons travel at the speed of light in a vacuum
Photons behave like particles
quantum – the minimum amount of energy that can be absorbed or released from an atom
- cannot be any value but are in discrete energy levels (like bundles or packets of energy)

11. 𝑐=𝑣λ
3.00× 10 8 =𝑣×4.9× 10 −7
𝒗=𝟔.𝟏× 𝟏𝟎 𝟏𝟒 𝑯𝒛

12. 3.17 m
1.70 x J
8.28 x J
1.0 x 10-5 m = 1.0 x 104 nm

13. Electrons and Energy Levels
Each electron has a distinct amount of energy that is related to the energy level (shell) it is in
Electrons with the lowest energy are found in the shell closest to the nucleus
Electrons with the highest energy are found in the shell furthest from the nucleus
The greater the distance from the nucleus, the greater the energy of the electron

14. Ground vs. Excited State
Ground state=when the electrons occupy the lowest energy levels possible
Excited state= on or more electrons gain energy and move to a higher energy level or shell (leaving the lower energy levels to be not completely full)

15. Ground and Excited State
When an electron gains energy, it jumps to a higher energy level or shell
This is a very unstable condition
We call this condition the excited state
Very rapidly, an electron in the excited state will lose energy and move back to a lower energy level or shell
When excited electrons fall from an excited state to a lower energy level, they release energy in the form of light

16. Ground  Excited State
Electron gains energy from heat, light, electricity
Electron “jumped” to a higher energy level (shell)

17. Excited  Ground State Electron releases energy in the form of light
Electron “falls” back and returns to ground state (normal position)

18. Bright Line Spectrum
Electrons falling from an excited state down to the ground state give off visible light
Different elements produce different colors of light or spectra
These spectra are unique for each element (just like a human fingerprint is unique to each person)

19. Phosphorescence Demo