Section 28.1
The Bohr Model of the Atom
Practice Test
1.
Determine the frequency of the photon emitted when an electron drops from
E
5
to
E
4
in an excited hydrogen atom.
a.
7.39×10
13
Hz
b.
3.55×10
14
Hz
c.
4.89×10
13
Hz
d.
5.86×10
14
Hz
Hint
2.
An atom drops from 7.64 eV to 5.98 eV. What is the frequency of the photon emitted by the atom?
a.
5.86×10
-14
Hz
b.
4.01×10
14
Hz
c.
2.50×10
14
Hz
d.
2.66×10
19
Hz
Hint
3.
In Figure 28-10, if an electron drops from an energy of -3.75 eV to -15 eV, what will be the wavelength of the emitted photon?
a.
270 nm
b.
66 nm
c.
85 nm
d.
110 nm
Hint
4.
When an electron drops from
E
4
to
E
3
in an excited hydrogen atom, the frequency of the emitted photon is 1.60×10
14
Hz. What is its wavelength?
a.
632 nm
b.
941 nm
c.
1880 nm
d.
188 nm
Hint
5.
An atom drops from 8.45 eV to 6.02 eV. What is the energy of the photon emitted by the atom?
a.
2.15 eV
b.
2.43 eV
c.
14.47 eV
d.
1.40 eV
Hint
6.
After bombarding metal foil with alpha particles, Rutherford's experimental results led him to conclude that the positive charge of the atom is __________.
a.
orbiting around the central core
b.
spread evenly throughout
c.
concentrated in the nucleus
d.
concentrated in the outer shell
Hint
7.
Calculate the radius of the orbital associated with the energy level
E
4
of the hydrogen atom. Use
h
2
/(4
&pi
2
Kmq
2
= 5.30×10
-11
m.
a.
1.33×10
-10
m
b.
8.50×10
-9
m
c.
1.91×10
-9
m
d.
8.50×10
-10
m
Hint
8.
A hydrogen atom has its electron in the
n
= 2 level. A photon with a wavelength of 297 nm strikes the atom and ionizes it. Assuming that the electron receives the excess energy from the ionization, what will be the kinetic energy of the electron in joules?
a.
4.27×10
-19
J
b.
3.18×10
-19
J
c.
1.26×10
-19
J
d.
6.69×10
-19
J
Hint
9.
Bohr suggested that light is emitted by an electron when __________.
a.
the electron reverses the direction of its orbit
b.
the electron completes one revolution in its orbit
c.
the electron's energy changes
d.
the electron's fixed orbit shifts
Hint
10.
Using the emission spectra shown in section 28.1, determine which among the following colors should appear the most brightly in the emission spectrum for the Sun.
a.
light purple
b.
orange
c.
yellow
d.
dark blue
Hint
11.
A photon with an energy of 14.0 eV enters a hydrogen atom in the ground state and ionizes it. With what kinetic energy will the electron be ejected from the atom?
a.
0.04 eV
b.
2.76 eV
c.
27.6 eV
d.
0.4 eV
Hint
12.
An atom is in a(n) __________ when it has absorbed energy and an electron made a transition to a higher energy level.
a.
quantum level
b.
ground state
c.
excited state
d.
orbit
Hint
13.
The energy of an electron in an orbit near the nucleus is __________ that of an electron farther away.
a.
less than
b.
equal to
c.
dependent on
d.
greater than
Hint
14.
Electrons in an atom have different quantized amounts of energy that are called __________.
a.
energy packets
b.
radii
c.
orbits
d.
energy levels
Hint
15.
Calculate the radius of the orbital associated with the energy level
E
5
of the hydrogen atom. Use
h
2/(4
π
A24
2
Kmq
2
= 5.30×10
-11
m.
a.
1.33×10
-10
m
b.
1.33×10
-9
m
c.
1.91×10
-10
m
d.
1.91×10
-9
m
Hint
16.
The __________ is the set of wavelengths at which a cool gas will absorb light.
a.
photon emission
b.
emission spectrum
c.
composition spectrum
d.
absorption spectrum
Hint
17.
A(n) __________ is an instrument used for studying emission spectra in detail.
a.
projector
b.
spectroscope
c.
electron microscope
d.
STM
Hint
18.
When an electron has the smallest allowable amount of energy, it is in the __________ state.
a.
neutral
b.
excited
c.
ground
d.
resting
Hint
19.
An atom drops from 8.62 eV to 7.05 eV. What is the wavelength of the photon emitted by the atom?
a.
792 nm
b.
250 nm
c.
1270 nm
d.
496 nm
Hint
20.
Use Figure 28-7 to answer this question. A friend shows you an emission spectrum that he says was produced by a light containing several gases, including hydrogen. Which of the following characteristics of the spectrum would disprove his statement?
a.
There are no red lines in the spectrum.
b.
There are no lines between 600 and 650 nm in the spectrum.
c.
There are three yellow lines in the spectrum.
d.
There are two blue lines in the spectrum.
Hint
21.
__________ lines are dark lines in the spectrum of sunlight.
a.
Radiated
b.
Omission
c.
Emitted
d.
Fraunhofer
Hint
22.
In Figure 28-11, if hydrogen's ground state energy were -12 eV, what will be the wavelength of the photon emitted when an electron drops from the 1st excited state to the ground?
a.
5900 nm
b.
140 nm
c.
78 nm
d.
11000 nm
Hint
23.
The set of light wavelengths emitted by an atom is called the atom's __________.
a.
scintillation
b.
emission spectrum
c.
alpha level
d.
spectral profile
Hint
24.
Calculate the radius of the orbital associated with the energy level
E
6
of the hydrogen atom. Use
h
2
/(4
π
2
Kmq
2
= 5.30×10
-11
m.
a.
1.91×10
-9
m
b.
1.91×10
-10
m
c.
1.33×10
-10
m
d.
1.33×10
-9
m
Hint
25.
According to Figure 28-4, how many lines would appear in the visible absorption spectrum for mercury?
a.
8
b.
16
c.
9
d.
5
Hint
26.
In the equation
E
n
= -13.6 eV(1/
n
2
),
n
is the __________.
a.
principal quantum number
b.
energy of an electron in its orbit
c.
mass of the electron
d.
electron orbital radius
Hint
