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Honors Chemistry
Test-The Atom
Name_______________________________
Part A. Multiple Choice
1. The Greek philosopher _____ proposed the first atomic theory around 400 B.C.
A. Aristotle
B. Archimedes
C. Democritus
D. Plato
2. Which of the following statements is NOT part of Dalton’s atomic theory?
A. All matter is composed of atoms.
B. Atoms cannot be broken down.
C. Atoms of different elements are different.
D. Isotopes of the same element have different masses.
3. _____ is generally credited with the discovery of the electron.
A. Chadwick
B. Moseley
C. Millikan
D. Thomson
4. The mass of a proton is _____ the mass of a neutron.
A. less than
B. more than
C. approximately equal to
5. _____ devised an oil drop experiment to determine the charge on an electron.
A. Chadwick
B. Moseley
C. Millikan
D. Thomson
6. Which of the following is a correct interpretation of the results to Rutherford’s experiments in which gold
atoms were bombarded with alpha particles?
A. Atoms have equal numbers of positive and negative charges.
B. Electrons in atoms are arranged in shells.
C. Neutrons are at the center of an atom.
D. The positive charge of an atom is concentrated in a small region.
7. Why does an atom have no overall charge?
A. Its subatomic particles carry no charge.
B. The positively charge protons cancel out the negatively charged neutrons.
C. The positively charged neutrons cancel out the negatively charged electrons.
D. The positively charged protons cancel out the negatively charged electrons.
8. Which particles are found in the nucleus of the atom?
A. electrons and protons
C. protons and neutrons
B. electrons and neutrons
D. protons, neutrons, and electrons
9. An atom composed of 16 protons, 16 electrons, and 16 neutrons is ______.
A. sulfur-48
B. germanium -32
C. sulfur-32
D. sulfur-16
10. Thallium has two isotopes, thallium-203 and thallium-205. Thallium’s atomic number is 81 and its average
atomic mass is 204.38 amu. Which statement about the thallium isotopes is true?
A. There is more thallium-203 in nature.
B. Atoms of both isotopes have 81 protons.
C. Thallium-205 atoms have fewer neutrons.
D. The most common atom of thallium has a mass of 204.38 amu.
11. Which of the following has a positive charge?
A. the proton
B. the neutron
C. the nucleus
D. both A and C
12. The _____ identifies the element and the _____ identifies the isotope.
A. atomic number, atomic number
C. atomic number, mass number
B. mass number, mass number
D. mass number, atomic number
Use the table below to answer questions 13 and 14
Name
Sodium
Chlorine
Protons
11
Neutrons
12
Electrons
Mass Number
17
35
13. How many electrons are in the atom of sodium?
A. 1
B. 11
C. 12
D. 23
14. How many neutrons are in the atom of chlorine?
A. 17
B. 18
C. 35
D. 52
15. Assume the following three isotopes of element Q exist:
258.63 amu, which of its isotopes is most abundant?
A. 248Q
B. 252Q
C. 259Q
16. The symbol “Si” is used to represent the element _____.
A. silver
B. silicon
C. sodium
248
Q, 252Q, and 259Q. If the atomic mass of Q is
D. they are all equally abundant
D. sulfur
17. Which one of the following does NOT contribute significantly to the mass of an atom?
A. electrons
B. nucleus
C. neutrons
D. protons
18. Uranium exists in nature in the form of several isotopes. The different isotopes have different ______.
A. atomic numbers
C. numbers of neutrons
B. numbers of electrons
D. numbers of protons
19. Which statement below best describes all atoms of a particular element?
A. They possess the same number of electrons, the same atomic number, the same mass, but nothing else
in common.
B. They possess the same mass, but nothing else in common.
C. They possess the same number of electrons, the same atomic number, but not necessarily the same
mass.
D. They possess the same atomic number and the same mass, but have nothing else in common.
20. The atom shown below which has 24 neutrons is _____.
A. 52Cr
B. 24Mg
C. 45Sc
D.
51
21. The atom shown below which has 24 protons is _____.
A. 52Cr
B. 24Mg
C. 45Sc
D.
51
V
V
22. Consider the atoms of 26Mg and 27Al. Both of these atoms have the same ____.
A. number of electrons
B. mass number
C. number of neutrons
D. number of protons
23. Consider the atoms of 59Co and 60Co. Both of these atoms have the same ____.
A. number of electrons
B. number of electrons
C. number of neutrons
D. both A and B
24. A neutral iodine atom has a mass number of 131. Which description below fits this atom?
A. 39 protons, 78 neutrons, 39 electrons
B. 53 protons, 78 neutrons, 53 electrons
C. 53 protons, 131 neutrons, 53 electrons
D. 53 protons, 53 neutrons, 78 electrons
Use the information in the table below to answer question # 25
Isotope
Mass (amu)
107
Ag
106.905
109
Ag
108.905
25. What is the average atomic mass of silver?
A. 105.865 amu
B. 107.865 amu
Abundance
52.00%
48.00 %
C. 107.905 amu
D. 110.905 amu
26. Which of the following does NOT describe a mole?
A. a unit used to count particles directly
B. Avogadro’s number of atoms of an element
C. the number of atoms in exactly 12 g of pure carbon-12
D. the SI unit for the amount of a substance
27. The conventional laboratory unit of mass is the ____.
A. amu
B. kilogram
C. gram
28. 6.02 x 1023 atoms is called _____ number.
A. Avogadro’s
B. Newton’s
D. ounce
C. Aristotle’s
29. There are 6.02 x 1023 atoms in one ____ of atoms.
A. mole
B. Newton
C. amu
D. Planck’s
D. kilogram
30. _____ is the element used as the standard for the atomic mass scale.
A. carbon
B. oxygen
C. sodium
D. aluminum
31. If a single atom of oxygen has a mass of 16 amu, then 6.02x1023 atoms of oxygen have a mass of _____ g.
A. 16
B. 6.02x1023
C. 96.32
D. 32
32. The mass in grams of one mole of any pure substance is called its _____ mass.
A. atomic
B. formula
C. molar
D. molecular
33. If 24 g of carbon is measured on a balance, how many atoms have been indirectly counted?
A. 2
B. 24
C. 6.02 x 1023
D. 1.204 x 1024
34. Dozen is to eggs as mole is to _____.
A. atoms
B. 6.02 x 1023
C. size
D. grams
35. Put the following amounts in increasing order (smallest to largest):
I.
2 moles of oxygen
II.
24 g of oxygen
III.
1.505 x 1024 atoms of oxygen
IV.
half of Avogadro’s number
A. III, IV, II, I
B. IV, II, I, III
C. III, I, IV, II
D. IV, I, III, II
Use the diagram below to answer questions 36-38.
36. How many neutrons does the most common atom of beryllium have?
A. 3
B. 4
C. 5
D. 9
37. One atom of beryllium has an average mass of _____.
A. 4 amu
B. 4 g
C. 9.01219 amu
D. 9.01218 g
38. What is the mass of a boron sample which contains 0.500 moles of beryliium atoms?
A. 2 g
B. 4.51 g
C. 3.01 x 1023 g
D. none of the above
Honors Chemistry
Test-The Atom
Name__________________________________
Part 2. Free Response
Directions. Solve the following problems. You must show all work to receive full credit. Record all answers to
the correct number of significant digits and label with the correct unit.
1. Indium has two naturally occurring isotopes and an average atomic mass of 114.818 amu. Indium-113 has a
mass of 112.904 amu and an abundance of 4.3%.
a) What is the percent abundance of indium’s other isotope?
b) What is the atomic mass of indium’s other isotope?
2. A neon sign contains 0.450 moles of neon. How many grams of neon gas are in this sign?
3. How many moles are in a copper penny containing 1.80 x 1021 atoms?
4. A cup of hot chocolate contains 0.035 g of sodium. How many atoms of sodium are in the hot chocolate?
5. Answer the following questions about a chlorine-37 atom.
a) How many protons does the atom contain? _________________
b) How many neutrons does the atom contain? ________________
c) How many electrons does the atom contain? ________________
d) Draw the Bohr diagram for the atom.
e) How many valence electrons does the atom have? _____________