14
I. Waves & Particles Electrons in Atoms

I. Waves & Particles Electrons in Atoms. A. Waves Wavelength ( ) - length of 1 complete wave Frequency ( ) - # of waves that pass a point during a

Embed Size (px)

Citation preview

Page 1: I. Waves & Particles Electrons in Atoms. A. Waves  Wavelength ( ) - length of 1 complete wave  Frequency ( ) - # of waves that pass a point during a

I. Waves & Particles

Electrons in Atoms

Page 2: I. Waves & Particles Electrons in Atoms. A. Waves  Wavelength ( ) - length of 1 complete wave  Frequency ( ) - # of waves that pass a point during a

A. Waves

Wavelength () - length of 1 complete wave

Frequency () - # of waves that pass a point during a certain time period hertz (Hz) = 1/s

Amplitude (A) - distance from the origin to the trough or crest

Page 3: I. Waves & Particles Electrons in Atoms. A. Waves  Wavelength ( ) - length of 1 complete wave  Frequency ( ) - # of waves that pass a point during a

A. Waves

Agreater

amplitude(intensity)

greater frequency

(color)

crest

origin

trough

A

Page 4: I. Waves & Particles Electrons in Atoms. A. Waves  Wavelength ( ) - length of 1 complete wave  Frequency ( ) - # of waves that pass a point during a

B. EM Spectrum

LOW

ENERGY

HIGH

ENERGY

Page 5: I. Waves & Particles Electrons in Atoms. A. Waves  Wavelength ( ) - length of 1 complete wave  Frequency ( ) - # of waves that pass a point during a

B. EM Spectrum

HIGH

ENERGY

R O Y G. B I V

red orange yellow green blue indigo violet

Page 6: I. Waves & Particles Electrons in Atoms. A. Waves  Wavelength ( ) - length of 1 complete wave  Frequency ( ) - # of waves that pass a point during a

B. EM Spectrum

Frequency & wavelength are inversely proportional

c = c: speed of light (3.00 x 108 m/s): wavelength (m, nm, etc.): frequency (Hz)

Page 7: I. Waves & Particles Electrons in Atoms. A. Waves  Wavelength ( ) - length of 1 complete wave  Frequency ( ) - # of waves that pass a point during a

B. EM Spectrum

GIVEN:

= ?

= 434 nm = 4.34 x 10-7 m c = 3.00 x 108m/s

WORK: = c

= 3.00 x 108 m/s

4.34x 10-7 m

= 6.91 x 1014 Hz

EX: Find the frequency of a photon with a wavelength of 434 nm.

Page 8: I. Waves & Particles Electrons in Atoms. A. Waves  Wavelength ( ) - length of 1 complete wave  Frequency ( ) - # of waves that pass a point during a

B. EM Spectrum

Energy and frequency are directly related

E = h E: Energy (joules, j)h: Planck’s constant(6.626 x 10-34 m2kg/s): frequency (Hz)

Page 9: I. Waves & Particles Electrons in Atoms. A. Waves  Wavelength ( ) - length of 1 complete wave  Frequency ( ) - # of waves that pass a point during a

B. EM Spectrum

GIVEN:

E = ?h = 6.626 x 10-34

m2kg/s

= 6.38 x 1014 Hz

WORK:E = h E = 6.626 x 10-34 m2kg/s x

6.38 x 1014 Hz

E = 4.23 x 10-21 J

EX: Find the energy of a photon with a frequency of 6.38 x 1014 Hz.

Page 10: I. Waves & Particles Electrons in Atoms. A. Waves  Wavelength ( ) - length of 1 complete wave  Frequency ( ) - # of waves that pass a point during a

B. EM Spectrum

GIVEN:

E = ?h = 6.626 x 10-34

m2kg/s

= ?C= 3.00x108m/s = 4.6 nm

= 4.6 x 10-9m

WORK: = C/ =(3.00x108m/s)/ (4.6x10-9m) =1.4 x 1016/sE=h E= 6.626 x 10-34 m2kg/s x 1.4 x 1017/s

E = 9.3 x 10-18 j

EX: Find the energy of a photon with a wavelength of 4.6 nm.

Page 11: I. Waves & Particles Electrons in Atoms. A. Waves  Wavelength ( ) - length of 1 complete wave  Frequency ( ) - # of waves that pass a point during a

C. Quantum Theory

Planck (1900)

Observed - emission of light from hot objects

Concluded - energy is emitted in small, specific amounts (quanta)

Quantum - minimum amount

of energy to change

Page 12: I. Waves & Particles Electrons in Atoms. A. Waves  Wavelength ( ) - length of 1 complete wave  Frequency ( ) - # of waves that pass a point during a

C. Quantum Theory

Planck (1900)

vs.

Newtonian Theory Quantum Theory

Page 13: I. Waves & Particles Electrons in Atoms. A. Waves  Wavelength ( ) - length of 1 complete wave  Frequency ( ) - # of waves that pass a point during a

C. Quantum Theory

Einstein (1905)

Observed - photoelectric effect

Page 14: I. Waves & Particles Electrons in Atoms. A. Waves  Wavelength ( ) - length of 1 complete wave  Frequency ( ) - # of waves that pass a point during a

C. Quantum Theory

Einstein (1905)

Concluded - light has properties of both waves and particles

“wave-particle duality”

Photon - particle of light that carries a quantum of energy