1.  The total number of electrons in a neutral atom of every element is always equal to the atom's
        (A) mass number        (B) # of neutrons        (C) # of protons        (D) # of nucleons

2.  Compared to an atom of calcium-40, an atom of calcium-39 contains fewer
        (A) electrons        (B) protons        (C) neutrons        (D) occupied energy levels

3.  An experiment using alpha particles to bombard a thin sheet of gold foil indicated that most of the volume of the
     atoms in the foil is taken up by
        (A) electrons        (B) protons        (C) neutrons        (D) empty space

4.  All isotopes of a given element must have the same
        (A) atomic number        (B) mass number        (C) number of neutrons        (D) number of nucleons

5.  An atom of carbon-14 contains
        (A) 8 protons, 6 neutrons, and 6 electrons        (B) 6 protons, 6 neutrons, and 8 electrons
        (C) 6 protons, 8 neutrons, and 8 electrons        (D) 6 protons, 8 neutrons, and 6 electrons

6.  What is the atomic number of an atom which contains 28 protons, 28 electrons, and 34 neutrons?
        (A) 28        (B) 56        (C) 62        (D) 90

7.  As the mass number of the isotopes of hydrogen increases, the number of protons
        (A) decreases         (B) increases        (C) remains the same

8.  What is the total number of electrons present in an atom of 59Co?
        (A) 27        (B) 32        (C) 59        (D) 86

9.  The development of the concept that elements have isotopes helps explain why
        (A) atomic nuclei are neutral                                       (B) average atomic masses are not whole numbers
        (C) atomic masses differ from the atomic numbers        (D) atomic nuclei are charged

10.  The standard now used in determining the atomic masses of all other elements is
        (A) hydrogen-1        (B) sulfur-32        (C) carbon-12        (D) oxygen-16

11.  The symbols 1H, 2H, and 3H indicate that the three kinds of hydrogen atoms have
        (A) the same atomic mass                   (B) different numbers of neutrons
        (C) different numbers of electrons        (D) different atomic numbers

12.  The most common form of hydrogen has
        (A) no neutrons        (B) one neutron        (C) two neutrons        (D) three neutrons

13.  An element consists of atoms, all of which have the same
        (A) mass number        (B) neutron number        (C) Avogadro's number        (D) atomic number

14.  The average atomic mass of an element
        (A) is the mass of the most abundant isotope        (B) may not equal the mass of any of its isotopes
        (C) cannot be calculated                                      (D) always adds up to 100

15.  If Z represents the atomic number and A represents the mass number of an isotope, then the number of
       neutrons in the atom is equal to
        (A) A + Z            (B) A - Z            (C) Z - A            (D) Z x A            (E) none of these

16.  The main idea of Dalton's theory about the nature and properties of atoms could be used to explain all of
       the following EXCEPT
        (A) the way in which substances combine            (B) the definite composition of substances
        (C) the composition of isotopes                           (D) that matter could not be created or destroyed

17.  Electrons were discovered as a result of investigations by
        (A) Dalton        (B) Bohr        (C) Chadwick        (D) Thomson        (E) Rutherford

18.  Combining Thomson's work on the charge-to-mass ratio of an electron with Millikan's work on the
       charge of an electron made it possible to determine the
        (A) mass of an electron                 (B) pathway of an electron       
        (C) diameter of an electron            (D) speed of an electron

19.  To determine the molar mass of an element, one must know the element's
        (A) Avogadro's number            (B) atomic number           
        (C) number of isotopes            (D) average atomic mass

20.  Which pair of substances illustrates the phenomenon of isotopes?
        (A) 12C and 14C            (B) SO3-2 and SO3            (C) H2O and H2O2            (D) 14C and 14C

21.  A single atom does not have a(n)
        (A) relative atomic mass            (B) atomic number           
        (C) mass number                      (D) average atomic mass

22.  The charge on the electron cloud
        (A) prevents compounds from forming                (B) balances the charges in the nucleus
        (C) attracts electron clouds in other atoms          (D) does not exist
              to form compounds

23.  Which of the following has the smallest mass?
        (A) a Br atom            (B) 1 x 10-20 mole of Br            (C) 1 x 10-20 grams of Br            (D) a Br2 molecule

24.  Which two compounds are examples of the law of multiple proportions?
        (A) FeCl3 and Fe2(SO4)3            (B) O2 and O3            (C) CO and CO2            (D) FeCl2 and Fe(NO3)2

25.  A positively-charged particle with a mass of 1.67 x 10-27 kg is a(n)
        (A) proton            (B) neutron            (C) electron            (D) positron            (E) nucleon

*26.  Deuterium contains one proton and
        (A) two neutrons            (B) one neutron            (C) no neutrons            (D) two electrons

27.  The carbon-12 atom is assigned a relative mass of exactly
        (A) 1 amu            (B) 6 amu            (C) 12 amu            (D) 100 amu

28.  The average atomic mass of an element depends on both the masses of its isotopes and each isotope's
        (A) atomic number            (B) radioactivity            (C) percent abundance            (D) mass number

29.  Sulfur-34 contains
        (A) 34 protons            (B) 18 protons            (C) 18 neutrons            (D) 16 neutrons

30.  The atomic number of neon is 10.  The atomic number of calcium is 20.  Compared with a mole of neon, a
       mole of calcium contains
        (A) twice as many atoms                   (B) half as many atoms           
        (C) an equal number of atoms            (D) 20 times as many atoms

31.  A quantity of sodium contains 6.022 x 1023 atoms.  The mass of the sodium is
        (A) 6.022 x 1023 grams            (B) 3.88 grams            (C) 22.99 grams            (D) not determinable

32.  The mass of a sample containing 3.5 moles of silicon atoms is
        (A) 28 grams            (B) 35 grams            (C) 72 grams            (D) 98 grams   

33.  The mass of a sample of nickel is 176.1 grams.  It contains
        (A) 1.761 x 1024 atoms            (B) 1.807 x 1024 atoms           
        (C) 5.869 x 1023 atoms            (D) 5.869 x 1024 atoms

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