1. Unit 3 Exam
Review

2. Question 1 Dalton’s atomic theory was accepted because
A. There was evidence to support it.
B. Democritus said that it was correct
C. Dalton invented the electron microscope
D. Dalton showed how molecules are formed

3. Question 1 Dalton’s atomic theory was accepted because
A. There was evidence to support it.
B. Democritus said that it was correct
C. Dalton invented the electron microscope
D. Dalton showed how molecules are formed

4. Question 2 Atoms are neutral (no net electric charge) when they
A. have an equal number of charged and non-charged particles
B. have neutrons in their nuclei
C. have an equal number of electrons and protons
D. have an equal number of neutrons and protons

5. Question 2 Atoms are neutral (no net electric charge) when they
A. have an equal number of charged and non-charged particles
B. have neutrons in their nuclei
C. have an equal number of electrons and protons
D. have an equal number of neutrons and protons

6. Question 3
The atomic theory of the ancient Greek philosopher Democritus was revised because A.
it claimed matter is made of atoms. C.
it explained what electrons are. B.
it claimed atoms could be divided. D.
scientists found new evidence.

7. Question 3
The atomic theory of the ancient Greek philosopher Democritus was revised because A.
it claimed matter is made of atoms. C.
it explained what electrons are. B.
it claimed atoms could be divided. D.
scientists found new evidence.

8. Question 4
In 1803 Dalton was the first person to develop an atomic theory based on lab experiments. Which of these statements is not part of Dalton’s atomic theory? A.
Atoms cannot be divided. B.
Atoms of an element are alike. C.
Atoms are made of electrons. D.
Atoms of different elements form compounds.

9. Question 4
In 1803 Dalton was the first person to develop an atomic theory based on lab experiments. Which of these statements is not part of Dalton’s atomic theory? A.
Atoms cannot be divided. B.
Atoms of an element are alike. C.
Atoms are made of electrons. D.
Atoms of different elements form compounds.

10. Question 5
A subatomic particle that has a negative charge is called a(n)
A. molecule
B. electron
C. element
D. compound

11. Question 5
A subatomic particle that has a negative charge is called a(n)
A. molecule
B. electron
C. element
D. compound

12. Question 6
Thomson made his discovery about the atom during an experiment using A.
thermal energy. C.
electrical current and a sealed gas tube B.
kinetic energy. D.
X rays.

13. Question 6
Thomson made his discovery about the atom during an experiment using A.
thermal energy. C.
electrical current and a sealed gas tube B.
kinetic energy. D.
X rays.

14. Question 7 What particle did Thomson discover? A. nucleus B. electron
C. proton
D. neutron

15. Question 7 What particle did Thomson discover? A. nucleus B. electron
C. proton
D. neutron

16. Question 8
Thompson’s “plum pudding” (or chocolate chip ice cream) atomic model showed the atom:
A. as negative particles scattered in a positive mass
B. has a negatively charged nucleus
C. as positive particles scattered in a negative mass
D. has neutrons and electrons

17. Question 8
Thompson’s “plum pudding” (or chocolate chip ice cream) atomic model showed the atom:
A. as negative particles scattered in a positive mass
B. has a negatively charged nucleus
C. as positive particles scattered in a negative mass
D. has neutrons and electrons

18. Question 9
By using his gold foil experiment, Rutherford was responsible for discovering that an atom contains
A. electrons
B. molecules
C. anodes
D. nucleus

19. Question 9
By using his gold foil experiment, Rutherford was responsible for discovering that an atom contains
A. electrons
B. molecules
C. anodes
D. nucleus

20. Question 10
Rutherford’s experiment produced evidence that the center of an atom A.
Contains a small region with a highly concentrated negative charge. B.
Contains a large region with a slight negative charge C.
Contains a small region with a highly concentrated positive charge. D.
Contains a small region with a highly concentrated neutral charge.

21. Question 10
Rutherford’s experiment produced evidence that the center of an atom A.
Contains a small region with a highly concentrated negative charge. B.
Contains a large region with a slight negative charge C.
Contains a small region with a highly concentrated positive charge. D.
Contains a small region with a highly concentrated neutral charge.

22. Question 11
According to Bohr’s theory, an electron’s path around the nucleus defines its A.
electric charge. C.
energy level B.
atomic mass. D.
speed.

23. Question 11
According to Bohr’s theory, an electron’s path around the nucleus defines its A.
electric charge. C.
energy level B.
atomic mass. D.
speed.

24. Question 12 Evidence to support Bohr’s model comes from: A.
Measuring the mass of different elements. C.
Measuring the energy in different colors of light given off by excited atoms B.
Knowing that neutrons are in the nucleus D.
Knowing that protons are in the nucleus.

25. Question 12 Evidence to support Bohr’s model comes from: A.
Measuring the mass of different elements. C.
Measuring the energy in different colors of light given off by excited atoms B.
Knowing that neutrons are in the nucleus D.
Knowing that protons are in the nucleus.

26. Question 13 Which of the following statements not true? A.
Protons have a positive charge. B.
A nucleus has a positive charge. C.
Neutrons have no charge. D.
Neutrons have a negative charge.

27. Question 13 Which of the following statements not true? A.
Protons have a positive charge. B.
A nucleus has a positive charge. C.
Neutrons have no charge. D.
Neutrons have a negative charge.

28. Question 14 Which of these particles could be a neutron?
A. Particle “A”
B. Particle “B”
C. Particle “C”

29. Question 14 Which of these particles could be a neutron?
A. Particle “A”
B. Particle “B”
C. Particle “C”

30. Question 15 Which of these particles could be an electron?
A. Particle “A”
B. Particle “B”
C. Particle “C”

31. Question 15 Which of these particles could be an electron?
A. Particle “A”
B. Particle “B”
C. Particle “C”

32. Question 16 Which of these particles could be an proton?
A. Particle “A”
B. Particle “B”
C. Particle “C”

33. Question 16 Which of these particles could be an proton?
A. Particle “A”
B. Particle “B”
C. Particle “C”

34. Question 17 What is an atom’s nucleus made of? A. protons and neutrons
only neutrons B.
only protons D.
anodes

35. Question 17 What is an atom’s nucleus made of? A. protons and neutrons
only neutrons B.
only protons D.
anodes

36. Question 18 The atomic mass of the element shown above would be:
A.9 B. 17 C. 25 D. 8

37. Question 18 The atomic mass of the element shown above would be:
A.9 B. 17 C. 25 D. 8

38. Question 19 The atomic number of the element shown above would be:
A.9 B. 17 C. 25 D. 8

39. Question 19 The atomic number of the element shown above would be:
A.9 B. 17 C. 25 D. 8

40. Question 20
An iron atom has an atomic mass of 56. Its atomic number is 26. How many neutrons does the iron atom have?
A. 30 B. 56 C. 26 D. 82

41. Question 20
An iron atom has an atomic mass of 56. Its atomic number is 26. How many neutrons does the iron atom have?
A. 30 B. 56 C. 26 D. 82

42. Question 21 An element’s atomic number is equal to its number of A.
protons. C.
nuclei B.
neutrons. D.
protons and neutrons.

43. Question 21 An element’s atomic number is equal to its number of A.
protons. C.
nuclei B.
neutrons. D.
protons and neutrons.

44. Question 22 Two different isotopes of an element have different A.
numbers of neutrons. C.
atomic numbers. B.
numbers of protons. D.
numbers of electrons.

45. Question 22 Two different isotopes of an element have different A.
numbers of neutrons. C.
atomic numbers. B.
numbers of protons. D.
numbers of electrons.

46. Question 23
What is the mass number of an element that has 19 protons, 19 electrons, and 20 neutrons?
A. 19 B. 20 C. 39 D. 58

47. Question 23
What is the mass number of an element that has 19 protons, 19 electrons, and 20 neutrons?
A. 19 B. 20 C. 39 D. 58

48. Question 24
Use a periodic table to answer this: A neutral sodium atom has how many electrons?
A. 0 B. 11 C. 12 D. 23

49. Question 24
Use a periodic table to answer this: A neutral sodium atom has how many electrons?
A. 0 B. 11 C. 12 D. 23

50. Question 25 An electron jumps to a new energy level when A.
the atom becomes charged. B.
the atom becomes unstable. C.
the electron’s location is pinpointed. D.
the atom gains or loses energy.

51. Question 25 An electron jumps to a new energy level when A.
the atom becomes charged. B.
the atom becomes unstable. C.
the electron’s location is pinpointed. D.
the atom gains or loses energy.

52. Question 26
The number of energy levels filled in an atom is determined by the number of
A. protons
B. electrons
C. neutrons
D. photons

53. Question 26
The number of energy levels filled in an atom is determined by the number of
A. protons
B. electrons
C. neutrons
D. photons

54. Question 27 Which statement about the atom’s nucleus is correct? A.
The nucleus is made of protons and neutrons, and has a negative charge. B.
The nucleus is made of protons and neutrons, and has a positive charge. C.
The nucleus is made of electrons, and has a positive charge. D.
The nucleus is made of electrons, and has a negative charge.

55. Question 27 Which statement about the atom’s nucleus is correct? A.
The nucleus is made of protons and neutrons, and has a negative charge. B.
The nucleus is made of protons and neutrons, and has a positive charge. C.
The nucleus is made of electrons, and has a positive charge. D.
The nucleus is made of electrons, and has a negative charge.

56. Question 28
Oxygen’s atomic number is 8. This means that an oxygen atom has A.
eight neutrons in its nucleus. B.
a total of eight protons plus neutrons. C.
eight protons in its nucleus. D.
a total of eight neutrons plus electrons.

57. Question 28
Oxygen’s atomic number is 8. This means that an oxygen atom has A.
eight neutrons in its nucleus. B.
a total of eight protons plus neutrons. C.
eight protons in its nucleus. D.
a total of eight neutrons plus electrons.

58. Question 29
Which statement about an element’s average atomic mass is correct? A.
It is determined by counting the number of isotopes in a sample of the element. B.
It is equal to one-twelfth the mass of the most common isotope. C.
It is a weighted average, so common isotopes have a greater effect than uncommon ones. D.
It is based on an isotope’s charge, so negatively charged isotopes have a greater effect than positive ones.

59. Question 29
Which statement about an element’s average atomic mass is correct? A.
It is determined by counting the number of isotopes in a sample of the element. B.
It is equal to one-twelfth the mass of the most common isotope. C.
It is a weighted average, so common isotopes have a greater effect than uncommon ones. D.
It is based on an isotope’s charge, so negatively charged isotopes have a greater effect than positive ones.

60. Question 30 An atom’s mass number equals the number of A.
protons plus the number of electrons. B.
protons plus the number of neutrons. C.
protons. D.
neutrons.

61. Question 30 An atom’s mass number equals the number of A.
protons plus the number of electrons. B.
protons plus the number of neutrons. C.
protons. D.
neutrons.