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THE ATOM
Vocabulary Review
For each phrase below, write the correct item.
absorption spectrum
excited state
principal quantum number
-particles
ground state
quantum mechanics
electron cloud
laser
quantum model
energy levels
nucleus
stimulated emission
1. _________________________
light amplification by stimulated emission of radiation
2. _________________________
massive, positively charged particles that move at high speeds
when emitted from radioactive materials
3. _________________________
process that occurs when an excited atom is struck by a photon
and releases a photon of equal energy
4. _________________________
the central, massive core of the atom
5. _________________________
the integer (n) that is used to determine quantized values for
orbital radius and the energy of an atom
6. _________________________
the lowest energy state occupied by an electron
7. _________________________
the model of the atom that predicts only the probability that an
electron is in a specific region
8. _________________________
a quantized property of an atom
9. _________________________
the region in which there is a high probability of finding an
electron
10. _________________________
the set of wavelengths absorbed by a gas
11. _________________________
the state of an atom that has absorbed energy
12. _________________________
the study of the properties of matter using its wave properties
Chapter 28  The Atom
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SECTION 1 Bohr's Model of the Atom
Circle the letter of the choice that best completes the statement or answers the question.
1. What does the fact that an emission spectrum contains only certain wavelengths show about
electrons?
a. Their energy is continuous.
c. They are present in the nucleus.
b. Their energy is quantized.
d. They have a negative charge.
2. The principal quantum number is represented by ____ .
a. h
c. n
b. mvr
d. 
3. The spectrum of an incandescent solid is typically ____ .
a. a band of colors with dark lines c. a set of colored lines
b. a continuous band of colors
d. a single colored line
4. What information can an emission spectrum reveal about the elements present in a sample?
a. both their identities and
relative concentrations
c. their identities only
b. neither their identities nor
their relative concentrations
d. their relative concentrations only
5. The Fraunhofer lines appear in the spectrum of ____ .
a. all flames
c. the Moon
b. sodium
d. the Sun
6. If the planetary theory of electrons were correct, at what wavelengths would light be released
by an atom?
a. at all wavelengths
c. in a band at the red end only
b. at certain specific values
d. in a band at the violet end only
7. The visible spectrum of hydrogen consists of ____ .
a. a continuous wide band
c. four lines
b. a single narrow band
d. two lines
Chapter 28  The Atom
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8. The energy of a photon of light released by an atom is equal to ____ .
a.
hc

b. hc
c.
h
f
d.

f
9. Planck’s constant is represented by the symbol ____ .
a. E
c. h
b. f
d. K
For each statement below, write true or rewrite the italicized part to make the statement true.
10. _________________________
An atom is mostly empty space with a tiny, massive, negatively
charged nucleus at its center.
11. _________________________
If white light passes through a gas, the gas absorbs the same
wavelength that it would emit if it were excited.
12. _________________________
Planck’s constant has a value of 0.053 nm.
13. _________________________
According to the Bohr model, the energy of an electron inside
an atom is quantized.
14. _________________________
An electron releases energy when it moves from the ground state to
an excited state.
15. _________________________
Bohr hypothesized that the laws of electromagnetism do not
operate inside atoms.
16. _________________________
r1 for a hydrogen atom is about 6.631034 Js.
17. _________________________
The constant from Coulomb’s law has a value of
9.0109 N • m2/C2.
18. _________________________
The orbits of electrons in excited states tend to be smaller than
those of electrons in the ground state.
19. _________________________
In the quantum–mechanical model of the atom, the atom’s
energy has only specific, quantized values.
20. _________________________
Quantum mechanics is extremely successful in calculating the
properties of atoms and molecules.
21. _________________________
Lasers produce full-spectrum light that is directional, powerful,
and coherent.
Chapter 28  The Atom
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Complete each statement by writing the correct term in the blank provided.
22. To investigate the nature of the atom, Rutherford’s team bombarded a metal foil with high–
speed _________________________.
23. To learn how electrons are arranged in the nucleus of the atom, researchers studied
_________________________ emitted by atoms.
24. When _________________________ is applied to a gas, the gas emits light, producing a unique
glow.
25. When the light emitted by a gas is passed through a _________________________ , the emission
spectrum of an atom is obtained.
26. An unknown gas can be identified by comparing its wavelengths with the wavelengths present
in the _________________________ of known samples.
27. Bohr suggested that _________________________ is emitted when the atom changes from one
stationary state to another.
SECTION 2 The Quantum Model of the Atom
Circle the letter of the choice that best completes the statement or answers the question.
1. Which quantity equals a whole-number multiple of the wavelength of an electron?
a. 2 r
c.  r
b. r
d.  r2
2. The modern quantum model of the atom precisely predicts ____ for an electron at any given
moment.
a. direction and position
c. position and velocity
b. position and momentum
d. the probability of being at a specific location
3. The probability of finding an electron in the electron cloud of an atom is ____ .
a. high
c. low
b. infinite
d. zero
Chapter 28  The Atom
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4. Application of the theories of electromagnetism to Bohr’s model predicted ____ .
a. a highly diffuse nucleus
c. collapse of the atom
b. a positive charge for electrons d. great stability for the atom
5. Wavelength of a particle is equal to ____ .
a.
h
c
c.
mv
h
b.
h
mv
d. mvr
6. Which is not true of quantum theory?
a. It can be used to give details of the structure of molecules.
b. It is based on the wave model.
c. It predicts the probability that the electron is at a given radius.
d. It proposes a planetary picture of the atom.
7. The circumference of the Bohr orbit equals ____ .

a. 2 r
c.
b. 
d.  r2
2 r
8. Which is true of n?
a. It cannot be expressed as a number. c. It is always a negative number.
b. It is always a whole number.
d. It may take on any value.
9. Light produced by an atomic gas consists of ____ wavelengths.
a. spontaneous
c. a continuum of
b. synchronized
d. only a few distinct
10. Single atoms have been detected and held almost motionless by means of ____ .
a. laser excitation
c. fiber optics
b. parallel mirrors
d. holograms
Chapter 28  The Atom
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For each statement below, write true or rewrite the italicized part to make the statement true.
11. __________________________
Stimulated emission results in coherent photons.
12. __________________________
Laser beams spread out greatly over long distances.
13. __________________________
Lasers are used in fiber optic communications.
14. __________________________
The acronym laser stands for light acceleration by stimulated
emission of radiation.
15. __________________________
Light emitted by an incandescent source has many wavelengths
and moves in all directions.
16. __________________________
Light in which the various waves are in phase is called
incoherent light.
17. __________________________
Light in which the waves are not in phase with each other is
called coherent light.
18. __________________________
The process that occurs when an excited atom is struck by a
photon and emits a neutron with equal energy is called
stimulated emission.
19. __________________________
The model of the atom that predicts only the probability that an
electron is in a specific region is the Bohr model.
20. __________________________
The region in which there is a high probability of finding an
electron around an atom is the electron vapor.
21. __________________________
The field in which the properties of matter are studied using its
particle properties is called quantum mechanics.
22. __________________________
Laser light is coherent light because all the stimulated photons
are emitted not in phase with the photons striking the atoms.
23. __________________________
Three ways in which atoms can be excited are thermal
excitation, electron collision, and collisions with lasers of exactly
the right energy.
Chapter 28  The Atom
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Study Guide
Teacher Support
THE ATOM
11. true
12. 6.631034 J• s
All numerical answers have been rounded to
the correct number of significant figures.
13. true
14. absorbs
Vocabulary Review
1. laser
15. true
2. -particles
16. 0.053 nm
3. stimulated emission
17. true
4. nucleus
18. larger
5. principal quantum number
19. true
6. ground state
20. true
7. quantum model
21. monochromatic
8. energy levels
22. alpha particles
9. electron cloud
23. the light
10. absorption spectrum
24. high voltage
11. excited state
25. prism, or diffraction grating
12. quantum mechanics
26. spectra
27. electromagnetic energy
SECTION 1 Bohr’s Model of the
SECTION 2 The Quantum Model of
Atom
the Atom
1. b
2. c
1. a
3. b
2. d
4. a
3. a
5. d
4. c
6. a
5. b
7. c
6. d
8. a
7. a
9. c
8. b
10. positively charged nucleus
Chapter 28  The Atom
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Study Guide
Teacher Support
9. d
10. a
11. true
12. little
13. true
14. amplification
15. true
16. not in phase
17. in phase
18. photon
19. quantum
20. cloud
21. wave
22. in phase with
23. photons
Chapter 28  The Atom
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