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Chapter 42: NUCLEAR PHYSICS
1. The smallest particle of any chemical element that can exist by itself and yet retain the qualities
that distinguish it as that element is:
A. an electron
B. a proton
C. a neutron
D. an atom
E. a molecule
ans: D
2. Of the following, which has the smallest rest energy?
A. A neutron
B. An electron
C. An ion
D. A proton
E. An atom
ans: B
3. The mass of an electron:
A. is almost the same as that of a neutron
B. is negative
C. equals that of a proton
D. is zero if the electron is at rest
E. is much less than that of a proton
ans: E
4. The mass of a neutron:
A. equals that of an electron
B. equals that of a proton
C. is a little more than that of a proton
D. is exactly that of a proton plus an electron
E. is as yet unmeasured
ans: C
5. The mass of a hydrogen atom, in kilograms, is approximately:
A. 10−27
B. 10−31
C. 10−24
D. 10−13
E. 10−8
ans: A
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6. 1 atomic mass unit is about:
A. 1.66 × 10−31 kg
B. 9.11 × 10−31 kg
C. 1.66 × 10−27 kg
D. 9.11 × 10−27 kg
E. 1.66 × 10−25 kg
ans: C
7. The atomic number of an element is:
A. the whole number nearest to its mass
B. the number of protons in its nucleus
C. the nearest whole number of hydrogen atoms having the same mass as a single atom of the
given element
D. the number of neutrons in its nucleus
E. its order of discovery
ans: B
8. Iron has atomic number 26. Naturally mined iron contains isotopes of mass numbers 54, 56,
57, and 58. Which of the following statements is FALSE?
A. Every atom of iron has 26 protons
B. Some iron atoms have 30 neutrons
C. Some iron atoms have 54 neutrons
D. The isotopes may be separated in a mass spectrometer
E. There are four kinds of naturally occurring iron atoms with the same chemical properties
ans: C
9. Let Z denote the atomic number and A denote the mass number of a nucleus. The number of
neutrons in this nucleus is:
A. Z
B. A − Z
C. A − 2Z
D. A
E. 2A − Z
ans: B
10. The isotopes of an element:
A. cannot be separated at all
B. occur well separated in nature
C. have similar chemical behavior
D. cannot be separated by physical methods
E. have equal masses
ans: C
624 Chapter 42: NUCLEAR PHYSICS
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Chapter 42: NUCLEAR PHYSICS
1. The smallest particle of any chemical element that can exist by itself and yet retain the qualities
that distinguish it as that element is:
A. an electron
B. a proton
C. a neutron
D. an atom
E. a molecule
ans: D
2. Of the following, which has the smallest rest energy?
A. A neutron
B. An electron
C. An ion
D. A proton
E. An atom
ans: B
3. The mass of an electron:
A. is almost the same as that of a neutron
B. is negative
C. equals that of a proton
D. is zero if the electron is at rest
E. is much less than that of a proton
ans: E
4. The mass of a neutron:
A. equals that of an electron
B. equals that of a proton
C. is a little more than that of a proton
D. is exactly that of a proton plus an electron
E. is as yet unmeasured
ans: C
5. The mass of a hydrogen atom, in kilograms, is approximately:
A. 10−27
B. 10−31
C. 10−24
D. 10−13
E. 10−8
ans: A
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6. 1 atomic mass unit is about:
A. 1.66 × 10−31 kg
B. 9.11 × 10−31 kg
C. 1.66 × 10−27 kg
D. 9.11 × 10−27 kg
E. 1.66 × 10−25 kg
ans: C
7. The atomic number of an element is:
A. the whole number nearest to its mass
B. the number of protons in its nucleus
C. the nearest whole number of hydrogen atoms having the same mass as a single atom of the
given element
D. the number of neutrons in its nucleus
E. its order of discovery
ans: B
8. Iron has atomic number 26. Naturally mined iron contains isotopes of mass numbers 54, 56,
57, and 58. Which of the following statements is FALSE?
A. Every atom of iron has 26 protons
B. Some iron atoms have 30 neutrons
C. Some iron atoms have 54 neutrons
D. The isotopes may be separated in a mass spectrometer
E. There are four kinds of naturally occurring iron atoms with the same chemical properties
ans: C
9. Let Z denote the atomic number and A denote the mass number of a nucleus. The number of
neutrons in this nucleus is:
A. Z
B. A − Z
C. A − 2Z
D. A
E. 2A − Z
ans: B
10. The isotopes of an element:
A. cannot be separated at all
B. occur well separated in nature
C. have similar chemical behavior
D. cannot be separated by physical methods
E. have equal masses
ans: C
624 Chapter 42: NUCLEAR PHYSICS
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