Name
Class
Date
Assessment
Chapter Test A
Chapter: Atoms: The Building Blocks of Matter
In the space provided, write the letter of the term or phrase that best completes each
statement or best answers each question.
______ 1. Neutral atoms contain equal numbers of
a. electrons and neutrons.
b. protons and neutrons.
c. protons and electrons.
d. protons, electrons, and neutrons.
______ 2. The atomic symbol for beryllium, 94 Be, indicates that the
a. atomic number is 4.
b. atomic number is 9.
c. mass number is 4.
d. atomic number is equal to 9 4.
______ 3. The atomic mass of an atom of carbon is 12 amu, and the atomic
mass of an atom of oxygen is 16 amu. To produce CO, 16 g of oxygen
combine with 12 g of carbon. To produce CO2, 32 g of oxygen combine
with 12g of carbon. The ratio of the mass of oxygen in CO2 to the mass
of oxygen in CO is
a. 1:1.
b. 2:1.
c. 1:2.
d. 8:3.
______ 4. Rutherford’s gold-foil experiment led him to conclude that
a. Thomson’s plum pudding model of the atom was accurate.
b. alpha particles were a poor choice for a bombardment material.
c. a dense region of positive charge existed somewhere in the atom.
d. light was emitted by electrons returning to ground state.
______ 5. Which of the following is not one of the five principles of Dalton’s
theory?
a. Atoms of different elements combine in simple, whole-number
ratios to form compounds.
b. All matter is made of indivisible, indestructible atoms.
c. All atoms have similar physical and chemical properties.
d. Chemical reactions consist of the combination, separation, or
rearrangement of atoms.
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Modern Chemistry
18
Chapter Test
Name
Class
Date
Chapter Test A, continued
______ 6. According to the law of definite proportions, any two samples of KCl
will have
a. the same mass.
b. slightly different molecular structures but the same two elements.
c. different densities.
d. the same elements in the same proportions by mass.
______ 7. According to the law of conservation of mass, when sodium, hydrogen,
and oxygen react to form a compound, the mass of the compound
will be
a. equal to the sum of the masses of the reactants.
b. greater than the sum of the masses of the reactants.
c. less than the sum of the masses of the reactants.
d. either less than or equal to the sum of the masses of the reactants.
______ 8. Thomson’s experiment showed that the charge-to-mass ratio of
electrons was
a. greater with noble gases than for other gases.
b. less with noble gases than for other gases.
c. the same in all gases.
d. dependent on the element’s atomic mass.
______ 9. An atom of potassium has 19 protons and 20 neutrons. Its mass
number is
a. 9.
b. 19.
c. 20.
d. 39.
______10. Which of the following is not equal to 1.00 mol of carbon-12?
a. 6.022 1023 carbon atoms
b. 12.0 g of carbon
c. 6.0 g of carbon
d. Both (b) and (c)
______11. Compared with a mole of lead atoms, a mole of iron atoms
a. has more atoms.
b. has fewer atoms.
c. has the same number of atoms.
d. cannot be determined because iron is magnetic.
______12. The molar mass of an element is numerically equal to
a. the element’s average atomic mass.
b. the element’s average atomic number.
c. the number of electrons possessed by an element.
d. the percentage composition of the element by mass.
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Modern Chemistry
19
Chapter Test
Name
Class
Date
Chapter Test A, continued
______13. To calculate the number of atoms present in 2.0 mol of an element,
you would
a. add Avogadro’s number of atoms per mole to 2.0 mole.
b. subtract Avogadro’s number of atoms per mole from 2.0 mole.
c. multiply Avogadro’s number of atoms per mole by 2.0 mole.
d. divide Avogadro’s number of atoms per mole by 2.0 mole.
______14. The units of molar mass are
a. g/mol.
b. mol/g.
c. amu/mol.
d. amu/g.
______15. To determine the mass in grams of an atom of any element, you would
a. multiply the mass of a mole of the element by Avogadro’s number.
b. divide the mass of a mole of the element by Avogadro’s number.
c. add the mass of a mole of the element to Avogadro’s number.
d. subtract the mass of a mole of the element from Avogadro’s number.
______16. The average atomic mass of an element is
a. the mass of one isotope of the element.
b. the weighted average of all naturally occurring isotopes of the
element.
c. the same as the atomic number of the element.
d. the sum of the number of neutrons and protons in an atom.
______ 17. The ancient Greek natural philosopher who first proposed the notion
of the atom was
a. Aristotle.
b. Socrates.
c. Democritus.
d. Plato.
______18. The word atom means
a. indivisible.
b. indestructible.
c. energetic.
d. charged.
______19. Which feature of Dalton’s atomic theory is different from modern
atomic theory?
a. Atoms cannot be destroyed.
b. Atoms cannot be subdivided.
c. Atoms cannot be rearranged in chemical reactions.
d. Atoms combine in whole-number ratios.
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Modern Chemistry
20
Chapter Test
Name
Class
Date
Chapter Test A, continued
______20. The molecular mass of CO2 is 44.01 amu. What is the mass of 2.0 mol
of CO2?
a. 44.01 amu
b. 44.01 g
c. 88.02 amu
d. 88.02 g
______21. The least massive particle in an atom is the
a. proton.
b. neutron.
c. electron.
d. None of the above
______22. The most massive particle in an atom is the
a. proton.
b. neutron.
c. electron.
d. None of the above
______23. Protons are bound together by
a. electric forces.
b. magnetic forces.
c. strong nuclear forces.
d. gravitational forces.
______24. How many moles of sodium hydroxide, NaOH, are in a 35.65 g sample
of NaOH? (The molar mass of NaOH is 40.01 g/mol.)
a. 0.8910 mol
b. 1.122 mol
c. 1426 mol
d. 5.366 1023 mol
______25. What is the mass of 3.56 mol of glucose, C6H12O6? (The molar mass of
C6H12O6 is 180.18 g/mol.)
a. 50.6 g
b. 641 g
c. 0.0198 g
d. 2.14 1024 g
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Modern Chemistry
21
Chapter Test