# Quantum Model of the Atom by XVgRWo

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```									Quantum Model of the Atom

 Bohr
 de Broglie
 Heisenberg
 Schrödinger
Neils Bohr (1885 –1962)

Bohr Model
of the
Hydrogen
Atom
Bohr model of the atom
In the Bohr
model,
electrons
can only
Energy

exist at
specific
energy levels
(orbit).
Photo Absorption and
Emission
Hydrogen Line Spectrum

Balmer Series
Line Spectra
Line spectrum of Hydrogen is
produced when an electron
drops from a higher-energy
orbit to a lower energy orbit.
Specifically,
Ephoton = E2 - E1 = h 
Bohr Checked it with Math.
 Used  mass and charge of the
electron together with Planck’s
constant and calculated where
the spectral lines should be and
they were!
 Problem -- only worked for
Hydrogen!
Bohr model of the atom
   The Bohr model is a
‘planetary’ type
model.

   Each principal
quantum represents
a new ‘orbit’ or layer.

   The nucleus is at the
center of the model.
Hydrogen Spectrum (cont.)
Each line of the Hydrogen
spectrum is produced by
and corresponds to the
emission of photons with
specific energies (E = h)
Bohr Model
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What the Heck is Light?
Hold It!
 Nay, Nay says “Classical”
theory.
 Hydrogen should be excited by
whatever amount of energy.
 Should be continuous spectrum
 What’s with the lines????
 Why   wouldn’t there be an
infinite number of energy levels
for electrons?
 Photoelectric effect and
Hydrogen spectrum.
Neils Bohr (1885 –1962)

Bohr Model
of the
Hydrogen
Atom
Louis de Broglie
(1892-1987)
Electrons should
be considered
waves confined
to the space
around an
atomic nucleus
The Quantum Atom (cont.)

 Since electrons are waves,
they can amplify and cancel
out when in and out of sync.
 Therefore only certain
energies of electrons are
possible.
Werner Heisenberg
Heisenberg
Uncertainty
Principle – It is
impossible to
determine the
position and
velocity of an
electron
simultaneously.
Separated at Birth….
Heisenberg uncertainty
principle
order to observe an electron,
 In
one would need to hit it with
photons having a very short
wavelength.
 Shortwavelength photons
would have a high frequency
and a great deal of energy.
Heisenberg uncertainty
principle
 Ifone were to hit an electron, it
would cause the motion and the
speed of the electron to change.
 Lower  energy photons would
have a smaller effect but would
not give precise information.
Heisenberg Uncertainty
Principle

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Erwin Schrödinger
(1887-1961)
Schrödinger
developed the
calculus to
describe the
wave behavior
and energies of
electrons in
atoms.
Schrödinger’s Equation

Yeah, but
it works!
Bohr vs. Schrödinger
Orbits vs. Orbitals
Bohr -- definite
distinct orbits
populated by
electron
particles.
Bohr vs. Schrödinger
Orbits vs. Orbitals
Schrödinger -- electron are
waves (de Broglie) with a
certain probability
(mathematical model) of
being found in three
dimensional regions around
the nucleus - orbitals
Comparing Models of the
Atom – A review

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