Download Bohr Model and Quantum Model

CHEMISTRY
“ELECTRONS IN ATOMS”
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proposed that the
energy of the
electron in the H
atom was quantized
allowed energy
levels for the
electron = ORBITS
(electron can only
have certain amounts
of energy, not any
possible amount)
RULE 1: Electrons can orbit only at certain
allowed distances from the nucleus.
 RULE 2: Atoms radiate energy when an
electron jumps from a higher-energy orbit
to a lower-energy orbit. Also, an atom
absorbs energy when an electron gets
boosted from a low-energy orbit to a highenergy orbit.

 Ground
state-the original energy
level of an electron before
becoming excited
 Excited state-describe an electron
that has become excited
Photons are a particle of
radiation or an individual
quantum of light
 Quantum is a finite quantity of
energy that can be gained or
lost by an atom

 Using
the Bohr’s Model of the atom, if
an electron in an atom of hydrogen goes
from energy level 6 to energy level
2, what is the wavelength and frequency
of the EM radiation emitted?
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Which transition occurs when a hydrogen atom
emits light with a wavelength of 434 nm?
A) The electron jumps from n=2 to n=4
B) The electron jumps from n=2 to n=5
C) The electron falls from n=4 to n=2
D) The electron falls from n=5 to n=2

applied known
wave equations to
electrons

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In 1926 the Quantum Model was
formed
It states that electrons do not have
precise orbits or paths
Electrons move about in a cloud
around the nucleus in what appears to
be a random pattern
The Quantum Model only predicts
where an electron is likely to be found
Heisenberg Uncertainty
Principle
Heisenberg stated that you
may know the location of an
electron or the velocity of
electron but you may not
know both simultaneously
 In
the quantum model, the
nucleus is not surrounded by
orbits, but by atomic orbitals
 Atomic Orbitals: a 3-D (three
dimensional) region around the
nucleus where a certain
electron can be located
 Electrons
emits energy in the form of
radiation
 Low
energy electrons are found near
the nucleus;
 high energy electrons are found
further away from the nucleus
 The
Quantum Model is based on
understanding the behavior of
light
 Light is composed of
Electromagnetic (EM) waves
 EM spectrum shows all forms of
radiation
Electromagnetic Spectrum
 Encompasses
all forms of
electromagnetic radiation, with
the only differences in the types
of radiations is their frequencies
and wavelengths.
 The Speed of Light remains the
same always.
Waves
 Wavelength:
() the distance between
wave crests
 measured in m or nanometers (nm)
 Amplitude: height of wave from origin
to crest
 Trough-the lowest point on a wave
 Crest-the highest point on a wave
Frequency
 Frequency:
() the number
of wave cycles that pass a
given point in a given time
 Frequency is measured in
Hertz (Hz)
 1 Hertz = 1/s