Download Quantum Mechanics and the Bohr Model - slater science

Physics and the Quantum
Mechanical Model
Objectives
•Describe the relationship between the
wavelength and frequency of light.
•I.D. the source of atomic emission
spectra.
•Explain how the frequencies of
emitted light are related to changes in
electron energies.
•Distinguish between quantum
mechanics and classical mechanics.
What are Electromagnetic
Waves?
• Electromagnetic waves
are formed when an
electric field (shown
as red) couples with a
magnetic field (shown
as blue).
• The magnetic and
electric fields of an
electromagnetic wave
are perpendicular to
each other and to the
direction of the wave.
Properties of Waves
• On your paper draw a horizontal line
approximately 5 inches long.
• Using the line as the midpoint draw two
waves superimposed on each other. Both
waves should have the same amplitude but
different frequencies.
• Draw another horizontal line and two waves
with the same wavelength but different
amplitudes.
Electromagnetic Spectrum
PRACTICE!
Atomic Spectra
• ATOMIC EMMISSION
SPECTRUM
• Light emitted atoms
consists of a mixture of
only specific
frequencies.
• Each specific frequency
of visible light
corresponds to a
particular color.
• When the light emitted
by an atom passes
through a prism it
• The lowest possible
energy of the electron is
the ground state. (n=1)
• Absorbing energy
moves it to the excited
state (n=2,3,4, 5, 6, 7)
• E = h x 
• Planck's equation
implies the higher the
frequency of a radiation,
the more energetic are
its quanta.
• E= quantum of Energy
• = frequency
• h= 6.626 x 10-34 J·s
Bohr’s Hydrogen Model and
Atomic Spectra
• Suppose an electron in its ground state (n=1)
absorbs enough energy to jump to level 2.
What type of radiation will it emit when it
returns to the ground state?
• Which series of lines can be observed in the
emission spectrum of hydrogen?
• Compare the energy of the Paschen and
Balmer series.
• What do you notice about the spacing of the
energy levels from n=1 to n=7?
Science Trek
• http://www.colorado.edu/physics/2000/q
uantumzone/bohr.html
Professor Edwards
Melissa
Sergio