Practice Test (Unit 1) Name
Atomic Theory (sample multiple choice questions)
Use the pictures to answer the following questions:
a) b) c) d) e)
_____ 1. Which model represents the modern view of the atom? A
_____ 2. Identify the model Thomson described after discovering the electron. C
_____ 3. Which model best represents an indestructible particle as proposed by Dalton? E
_____ 4. Bohr would describe the path of electrons as orbits. Which model best represents this idea? B
_____ 5. Which model would Democritus have agreed represents the atom? E
_____ 6. How did Rutherford represent the electron after completing his gold foil experiment? D
_____ 7. The number of protons in the nucleus of an element.
a. atomic number. b. mass number. c. atomic mass. d. atomic weight.
_____ 8. The mass number of the element is the sum of the number of
a. protons and electrons. b. protons and neutrons.
c. electrons and neutrons. d. protons, electrons, and nucleons.
_____ 9. A positively charged subatomic particle.
a. electrons. b. protons. c. neutrons. d. nucleons.
_____ 10. A subatomic particle with no charge.
a. electron. b. proton. c. neutron. d. nucleon.
_____ 11. Defined as 1/12 the mass of a carbon-12 atom.
a. hydrogen atoms. b. quarks. c. electrons. d. atomic mass unit (amu).
_____ 12. Isotopes are atoms of the same element that have different numbers of _____ in their nucleus.
a. electrons. b. protons. c. neutrons. d. nucleons.
_____ 13. The weighted average of the mass of the atoms in a naturally occurring sample of an element.
a. atomic number. b. mass number. c. atomic mass. d. none of these.
_____ 14. Who coined the word “atomos” when describing particles that were indivisible?
a. Atomos b. Dalton c. Democritus d. Thomson
_____ 15. Dalton theorized that atoms are indivisible and that all atoms of an element are identical. We now know that _____.
a. Atoms are still indivisible.
b. Atoms of the same element can have different numbers of neutrons giving them a different mass.
c. Dalton’s theories are correct.
d. All atoms of an element are not identical but they must all have the same mass.
_____ 16. The scientist whose atomic theory consists of a dense positive nucleus surrounded by electrons located a large distance away is
a. Dalton. b. Rutherford. c. Democritus. d. Thomson.
_____ 17. Which scientist was given credit for discovering the electron
a. Dalton. b. Rutherford. c. Goldstein. d. Thomson. e. Chadwick
_____ 18. Tables of “atomic weights” of the elements give a value of 55.847 for iron, as an example. This value is not a whole number because
a. a mixture of iron isotopes is found naturally.
b. of the inability to make precise measurements.
c. iron atoms contain only 0.45 neutrons.
d. of differences in reporting weights compared to masses.
_____ 19. The current standard or reference atom for comparing relative masses of atoms is
a. hydrogen-1. b. carbon-12. c. oxygen-16. d. nitrogen-14.
_____ 20. Robert Milikan used an oil drop experiment to find the charge to mass ratio for this subatomic particle.
a. quark b. proton c. electron d. neutron e. muon
_____ 21. Which two particles which are found in the nucleus of an atom?
a. quark and lepton b. proton and electron c. electron and neutron d. proton and neutron
_____ 22. Which of the following would not have been considered a consequence of Rutherford’s gold foil experiment.
a. The atom consists of mostly empty space.
b. The mass of the atom is distributed evenly throughout the atom. (He said there was a nucleus)
c. The nucleus contains all the positive charge found in the atom.
d. The mass of the atom is concentrated in one small area called the nucleus.
_____ 23. The radioactive source of polonium that Rutherford used in his gold foil experiment emitted positively charged radiation called
a. beta particles b. gamma particles c. photons d. alpha particles
_____ 24. Identify the scientist who was credited for proposing the first theory about the atom based on scientific evidence and experiments.
a. John Dalton. b. Ernest Rutherford. c. Antoine Lavoisier. d. J. J. Thomson.
_____ 25. What is the atomic number and mass number of an atom with 11 protons and 12 neutrons?
a. atomic number = 11 and mass number = 12.
b. atomic number = 12 and mass number = 11.
c. atomic number = 11 and mass number = 23.
d. atomic number = 23 and mass number = 12.