Download Unit 4 Test REVIEW

Chemistry Unit 4 TEST Review
Atomic Structure—Nuclear Chemistry
1. The atomic mass of an element is equal to the ______________________________________
___________________________________________________________________________
2. Who was the first person to suggest the idea of atoms in the fourth century B.C.?
3. As a consequence of the discovery of the nucleus by Rutherford, the region outside the nucleus is
believed to be largely __________ space in which the ___________ are located.
4. How do you calculate the number of neutrons in an atom?
5. One atomic mass unit is equal to __________ the mass of once carbon-12 atom.
6. Isotopes of the same element have different numbers of ________________.
7. Dalton theorized that atoms are indivisible and that all atoms of an element are identical. We now
know that atoms are ___________________.
8. The atomic number of an element is the total number of which particles in the nucleus?
9. What charge and mass do protons, electrons and neutrons have? Where are each located?
10. Chemists use relative comparisons of masses of atoms because the actual masses of protons and
neutrons are very ____________.
11. All atoms are neutral, with the number of _____________ equaling the number of ___________.
12. All atoms of the same element have the same number of _______________.
13. Dalton’s atomic theory included which ideas?
14. Using the periodic table, determine the number of neutrons in S-32.
15. Isotopes of the same element have different __________ numbers.
16. The nucleus of an atom is composed of _______________________________.
17. What symbol does zinc have and how many protons and electrons does it have?
18. True or False: Dalton stated that all atoms are always in motion.
19. The nucleus of an element with atomic number of 25 and a mass number of 75 contains how many
protons, electrons and neutrons? Which element is this?
20. Which subatomic particles have the same mass?
21. True or False: Atoms of the same element can have different masses.
22. True or False: Atoms of isotopes of an element have different numbers of protons
23. True or False: The nucleus of an atom has a positive charge
24. True or False: Atoms are mostly empty space.
25. As a result of his experiments involving firing positively charge particles at metal foil, Rutherford
concluded that most of the mass of an atom was in the ___________.
26. What happens to the number of protons of an isotope when the mass number increases?
27. Which law is illustrated by the fact that water is always in a ratio of 2 to 1 of hydrogen to oxygen?
28. Which scientists was credited with the discovery of the electron as a result of work with cathode
rays?
29. ___________________ gold-foil experiment demonstrated that most of the atom is empty space.
30. Atomic mass is a relative scale based on which nuclide?
31. What is the mass number of an atom that has 20 protons, 22 neutrons and 20 electrons?
32. The word atom comes from the Greek word atomos meaning __________________.
33. In the synthesis of sulfur trifluoride, 33.0 g of sulfur combines with 24.0 g of fluorine. How many
grams of sulfur trifluoride will be produced?
34. Which subatomic particle has the smallest mass?
35. Potassium has a relative atomic mass that is not a whole number because some of its atoms have
more _________________ than others.
36. A reaction in which two light nuclei combine to form a heavier nucleus is termed ___________.
37. The most penetrating and highest energy form of radiation is ____________________________.
38. What is the symbol of the alpha particle?
39. What thickness of what material is necessary to stop an alpha particle?
40. If the half-life of a radioactive material is 15 years, how many years will it take for one half of the
original amount of material to decay?
41. Mass number is equal to the number of __________________________________.
42. What term refers to the “splitting” of atoms?
43. If the half-life of potassium-24 is 10 hours, how much remains from an 12.0 g sample after 50
hours?
44. The release of particles and rays that occurs when an unstable nucleus breaks down is called
_________________________.
45. In the equation E = mc2, c represents _________________________________.
46. What is the half-life of a radioactive substance, if after 36 years, 12.5 g remains from a 100 g
starting sample?
47. What thickness of what material will stop gamma radiation?
48. In a balanced nuclear equation, what must equal on both sides of the equation?
49. The smallest part of an element that still has the properties of that element is a/an __________.
50. The Greek philosopher that theorized all things are comprised of tiny particles called atoms was
__________________.
51. In an uncombined, neutral atom ______________ must equal ___________________.
52. Write the hyphen notation of an isotope that has 8 protons, 8 electrons and 12 neutrons?
53. What is the mass number of an atom that contains 29 protons, 29 electrons and 40 neutrons?
54. Given the equation:
228
Th  228Pa + X
90
91
What particle is represent by the letter X?
55. How many neutrons are in the nucleus of phosphorus-38?
56. 230Th  4He + ________
90
2
57. 234 U  234Np + ________
92
93
58. Element X has 3 naturally occurring isotopes, which are listed in the table below. What is the
average atomic mass of element X?
Isotope
% Abundance
X-38
90.21%
X-40
5.70%
X-41
4.09%
59. A sample decays to 5.0 grams in 60 hours. What was the mass of the original sample?
(half-life = 15 hours)
60. How many protons and neutrons does the following atom contain?
131
I
61. Which atom contains exactly 17 protons?