Download CHAPTER 4 EXAM: THE NATURE OF THE ATOM (modified)

CHAPTER 4 EXAM: THE NATURE OF THE ATOM (modified)
CHEMISTRY
Multiple Choice
Identify the choice that best completes the statement or answers the question.
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1. The box for an element from the periodic table is shown. Which is the atomic mass?
a. B
c. C
b. D
2. The box for an element from the periodic table is shown. Which is the atomic number?
a. B
c. A
b. D
3. Which scientist described an atom made of a solid positively charged substance with electrons dispersed
throughout he called the Plum Pudding Model?
a. Thomson
c. Bohr
b. Chadwick
4. Which scientist proved the existence of the neutron?
a. Thomson
c. Chadwick
b. Bohr
5. Which is the number of neutrons in
?
a. 80
c. 45
b. 115
6. Which one(s) have a mass of 1 amu?
a. electron
c. proton and neutron
b. proton
7. Which scientist measured the charge on an electron in the Oil Drop Experiment?
a. Bohr
c. Rutherford
b. Millikan
8. Democritus thought matter was composed of ___________.
a. atomos
c. alpha particles
b. gamma rays
9. Which is the number of protons in
a. 30
b. 82
Atoms
?
c. 26
Atom
1
2
3
4
Protons
8
10
9
8
Neutrons
10
9
9
11
Electrons
8
10
9
8
____ 10. Which two are isotopes of one another?
a. Atoms 2 & 3
b. Atoms 1 & 2
Atom
Sodium
Chlorine
Protons
17
Atoms
Neutrons
12
c. Atoms 1 & 4
Electrons
17
Mass Number
23
35
____ 11. How many neutrons are in an atom of chlorine?
a. 18
c. 17
b. 35
____ 12. How many electrons are in an neutral atom of sodium?
a. 11
c. 12
b. 22
____ 13. Which element has 14 electrons?
a. Sulfur
c. Silicon
b. Nitrogen
____ 14. According to the modern concept of the atom, which are located in the nucleus of an atom?
a. protons and neutrons
c. electrons and protons
b. neutrons and electrons
____ 15. Which is the smallest part of an element that retains all the properties of the element?
a. electron
c. neutron
b. atom
____ 16. An industrially important element contains 26 electrons and rusts in the presence of air and moisture. Identify
the element.
a. Aluminum
c. Iron
b. Sodium
____ 17. Alpha particles are composed of ___________.
a. 2 protons and 2 neutrons
c. electrons only
b. 2 neutrons and 2 electrons
____ 18. Beta particles have a ______ charge.
a. 2+
c. 1b. neutral
____ 19. In a neutral atom, the number of protons will equal the _____________.
a. electrons
c. atomic mass
b. neutrons
____ 20. Which is the following was NOT considered a basic element by the early Greeks?
a. light
c. fire
b. water
____ 21. Which of the following is NOT supported by Rutherford’s Gold Foil Experiment?
a. atoms are mostly empty space
c. the positive charges are spread out
throughout the atom
b. the nucleus is positively charged
____ 22. How many electrons does iodine-127 have?
a. 106
c. 74
b. 53
____ 23. Which is the correct symbol for the atom with 42 protons and 49 neutrons?
a.
c.
b.
____ 24. Which form of radiation has the most mass?
a. gamma
c. X-ray
b. alpha
____ 25. There have been changes we have made to Dalton’s atomic theory since 1803. Which of the following is no
longer true?
I. Atoms are indivisible and indestructible.
II. Atoms of the same element are identical.
III. Atoms may combine to form compounds.
IV. Atoms rearrange during chemical change.
a. I. only
c. III. and IV. only
b. I. and II only
____ 26. Which form of radiation is the most penetrating?
a. alpha
c. X-ray
b. gamma
Short Answer
27. What is the average atomic mass of this element? SHOW ALL WORK!!!
Isotope
Mass (amu)
Percent Abundance
Phosphorus-29
29
5.0%
Phosphorus-31
31
71.0%
Phosphorus-32
32
24.0%
28. Element X has an average atomic mass of 64.32 amu. If this element consists of only two isotopes, X-64 and
X-65, which isotope is present in the greater abundance? Explain how you can tell.
29. Democritus and Dalton proposed many similar points in their atomic theories. Infer why Dalton’s were more
accepted.
Other
30. BONUS
What did J.J. Thomson observe when using magnets with his cathode ray tube? Why did this happen?