Transcript II. Bohr Model of the Atom

Ch. 4 - Electrons in Atoms
II. Bohr Model of the Atom
(p. 94 - 97)
C. Johannesson
C. Johannesson
Bohr's Atom: Quantum Behavior in
Hydrogen
Concept Simulation - reenacts electron's
'jump' and 'fall' to precise energy levels in
a hydrogen atom.
Visionlearning Viewer
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A. Line-Emission Spectrum
Hydrogen Gas
excited state
ENERGY IN
PHOTON OUT
ground state
Atoms are “excited”
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with an electric current
B. Bohr Model
e- exist only in orbits with specific
amounts of energy called energy levels
Therefore…
e- can only gain or lose certain
amounts of energy
only certain photons are produced
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B. Bohr Model
65
4
3
2
1
Energy of photon
depends on the
difference in
energy levels
Bohr’s calculated
energies matched
the IR, visible, and
UV lines for the H
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C. Other Elements
Each element has a unique bright-line
emission spectrum.
“Atomic Fingerprint”
Helium
Bohr’s calculations only
worked for hydrogen! 
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According to the Bohr model of the atom,
which particles are allowed to exist in any
one of a number of energy levels?
a)
b)
c)
d)
Electrons
Protons
Neutrons
Both (b) and (c)
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The line-emission spectrum of an atom
is caused by the energies released
when electrons
a) “jump” from a lower energy level
to a higher energy level
b) “jump” from a higher energy level
to a lower energy level
c) “jump” from the ground state to
an excited state
d) None of the above
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Because excited hydrogen atoms always
produce the same line-emission spectum,
scientists concluded that hydrogen
a) has no electrons
b) does not release energy
c) releases energy of only certain
values
d) can exist only in the ground state
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Bohr’s model correctly explains the spectra
of atoms with how many electron(s)?
a)
b)
c)
d)
one
two
three
four or more
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The process of an atom releasing
energy when it moves to a lower energy
state is called
a)
b)
c)
d)
absorption
emission
translation
regression
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In the Bohr model of the atom, in which
orbit is an electron in its lowest energy
state?
a)
b)
c)
d)
In the orbit closest to the nucleus
In the orbit farthest from the nucleus
in the electron cloud
midway between two orbits
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C. Johannesson