Energy generated by quantum electronic transitions in an atom

Units for Measuring Waves

1 sec

Frequency = wavelengths/sec = Hertz

3 cycles per second = 3 hertz

AM and FM Radio frequencies

• In general means electromagnetic radiation

• The speed of light, c, is a constant:– 2.99792458 x 108meters/second in a vacuum

• A measured number!! We will use 3.00x108 m/s

– 186,000 miles/second in a vacuum.– This is speed NOT frequency!

• The wavelength or frequency of light can be calculated from the formula:

c = wavelength (λ) * frequency (f)

c = λf

• Energy (E) of a single photon is the product of wavelength (f) and Planck’s constant (h).

E = hf

h = 6.63E-34 J-sec

• Now combine c = λf and E = hf

f = c/λ so E = hc/λ

• We now have three equations in terms of speed, wavelength, frequency and energy that characterize light

Electromagnetic Spectrum

Energy In Energy Out

Electron Transition Producing Light

Different Quantum Transitions Cause Different Wavelengths of Light

VISIBLE LIGHT380nm 750nm

Violet

Blue

Green

Orange

Red

Very Bright Light

Prism

Continuous white light spectrum

Bohr’s Model of the Atom

DeBroglie’s Model of the Atom

END FINI DONE

S - Orbital

P – Orbital P-OrbitalDiagram.exe

D - Orbital

F - Orbital