Science 9
TEST: Chapter 3 M odels For Atoms
Page 1 of 4
I.
M ultiple Choice. (30 points) Choose any 30 of the 34 questions, and on your looseleaf print the letter of the
best answer beside the number of each question you choose. Omit any 4 of your choice.
1.
For hundreds of years up to about A.D.1600, a group of people carried out thousands of experiments and
invented many pieces of laboratory equipment that we still use today in an effort to turn metals such as iron and
lead into gold. W hat is the name given to these people?
(a) philosophers (b) alchemists (c) biochemists (d) metallurgists
2.
Dalton's atomic theory was one of the most important theories in chemistry. In this theory, atoms were
considered to be
(a) tiny solid indivisible spheres. (b) the same for all elements. (c) made up of smaller particles.
(d) mostly empty space.
3. W hich of the following statements is not part of Dalton's atomic theory?
(a) All substances are composed of small, indivisible particles called atoms.
(b) The atoms of a given element are identical in every respect.
(c) The three main particles in atoms are protons, neutrons, and electrons.
(d) In chemical reactions, atoms combine in simple, whole-number ratios.
4. The atomic model has been modified many times over the years. This happened because
(a) scientists have become smarter with time.
(b) new evidence became available to scientists.
(c) the actual nature of the atom has changed with time.
(d) more elements were discovered.
5.
W hich scientist first proposed the existence of the nucleus in atoms?
(a) Rutherford (b) Bohr (c) Thomson (d) Dalton
6.
In a famous experiment carried out in 1911, Ernest Rutherford bombarded a thin sheet of gold with high-speed,
positively charged particles. Based on the behaviour of these particles, Rutherford proposed that atoms
possessed
(a) a very small, positively charged, dense region in the centre of the atom.
(b) a very small, negatively charged, dense region in the centre of the atom.
(c) very small, positively charged particles that moved at high speed.
(d) equal numbers of positive and negative particles.
7.
According to the Rutherford model of the atom, the volume of an atom is mostly
(a) protons. (b) a nucleus.
(c) neutrons. (d) empty space.
8.
Several models of the atom have been suggested by scientists since the beginning of the nineteenth century.
W hat is the correct chronological order (earliest to latest) of the models proposed by the scientists listed below?
(a) Dalton, Bohr, Thomson, Rutherford
(b) Dalton, Thomson, Rutherford, Bohr
(c) Thomson, Dalton, Rutherford, Bohr
(d) Dalton, Rutherford, Thomson, Bohr
9.
The "plum pudding" model of the atom was proposed by
(a) Dalton
(b) Thomson (c) Rutherford (d) Bohr
10. In a model of the atom sometimes referred to as the "raisin bun" model, the raisins represent the
(a) protons (b) neutrons (c) nucleus (d) electrons
11. Protons are
(a) positively charged particles found outside the nucleus in an atom.
(b) negatively charged particles found outside the nucleus in an atom.
(c) neutral particles found in the nucleus in an atom.
(d) positively charged particles found in the nucleus in an atom.
Science 9
TEST: Chapter 3 M odels For Atoms
Page 2 of 4
12. Electrons are
(a) positively charged particles found outside the nucleus in an atom.
(b) negatively charged particles found outside the nucleus in an atom.
(c) neutral particles found in the nucleus in an atom.
(d) negatively charged particles found in the nucleus in an atom.
13. Neutrons are
(a) negatively charged particles found outside the nucleus in an atom.
(b) neutral particles found outside the nucleus in an atom.
(c) neutral particles found in the nucleus in an atom.
(d) positively charged particles found inside the nucleus in an atom.
14. W hich of the answers below correctly identify the diagrams to represent the atomic models proposed by Dalton,
Thomson, Rutherford, and Bohr?
(a) a=Rutherford, b=Bohr, c=Dalton, d=Thomson
(b) a=Dalton, b=Rutherford, c=Thomson, d=Bohr
(c) a=Dalton, b=Thomson, c=Rutherford, d=Bohr
(d) a=Thomson, b=Rutherford, c=Dalton, d=Bohr
15. All of the following terms are associated with the atom. Which one has the smallest mass?
(a) electron (b) proton (c) neutron (d) nucleus
16. The mass of a neutron is approximately
(a) 2000 times greater than the mass of a proton.
(b) 2000 times greater than the mass of an electron.
(c) 1/2000 of the mass of an electron.
(d) 1/2000 of the mass of a proton.
17. The number of electrons in an atom is the same as
(a) the number of neutrons in the atom.
(b) the mass number of the atom.
(c) the number of protons in the atom.
(d) the difference between the mass number and atomic number.
18. The particles that make up most of the mass of an atom are
(a) the protons and electrons. (b) the neutrons and electrons.
(d) only the neutrons.
(c) the protons and neutrons.
19. If the atomic number of an atom is represented by X and the mass number is represented by Y, the number of
neutrons in an atom of the element is
(a) Y-X (b) X-Y (c) X+Y (d) Y
20. The numbers of protons, electrons, and neutrons in an atom of 3 5 Cl are
(a) 17 protons, 18 electrons, 18 neutrons.
(b) 17 protons, 17 electrons, 35 neutrons.
(c) 18 protons, 17 electrons, 35 neutrons.
(d) 17 protons, 17 electrons, 18 neutrons.
21. An atom with an atomic number of 38 and a mass number of 88 contains
(a) 38 neutrons (b) 50 electrons (c) 50 neutrons (d) 88 protons
Science 9
TEST: Chapter 3 M odels For Atoms
Page 3 of 4
22. In Bohr's planetary model of the atom, he suggested that
(a) the closer an electron is to the nucleus, the higher its energy.
(b) electrons always stay in the same energy level.
(c) the orbit closest to the nucleus can hold eight electrons.
(d) electrons could be found only in certain orbits or energy levels.
23. Bohr proposed that the line spectrum of an element is caused by (light is emitted or given off when . . .)
(a) electrons leaving the atom.
(b) electrons moving from the nucleus to one of the energy levels.
(c) electrons moving from a higher energy level back to a lower energy level.
(d) electrons moving from one of the energy levels back to the nucleus.
24. The difference between an atom in its ground state and the same atom in an excited state is that
(a) there are more electrons in the excited-state atom than the ground-state atom.
(b) all of the electrons in the excited-state atom are in higher energy levels than in the ground-state atom
(c) there are more neutrons in the excited-state atom, making it heavier than the ground-state atom
(d) in the excited-state atom, at least one electron is in a higher energy level than in the ground-state atom
25. W hich of the following is the correct arrangement of electrons in a phosphorus atom, atomic number 15?
(a) 2, 8, 4, 1 (b) 2, 8, 5 (c) 5, 8, 2 (d) 2, 5, 8
26. The number of electrons in the outermost energy level of a sulfur atom is
(a) 2 (b) 8 (c) 6 (d) 16
27. The particles formed when atoms lose or gain electrons are called
(a) compounds (b) beta particles (c) isotopes (d) ions
28. An atom can form a positive ion by
(a) losing electrons
(b) gaining electrons
(c) losing protons
(d) gaining protons
29. An atom can form a negative ion by
(a) losing electrons
(b) gaining electrons
(c) losing protons
(d) gaining protons
30. Potassium ions have a charge of +1. This is because the ions have
(a) one more proton than the number of electrons
(b) one more electron than the number of protons
(c) one more proton than the number of neutrons
(d) one more neutron than the number of protons.
31. Sulphide ions have a charge of -2. This is because the ions have
(a) two more protons than the number of electrons.
(b) two more electrons than the number of protons.
(c) two more protons than the number of neutrons.
(d) two more neutrons than the number of protons.
32. Isotopes of the same element have
(a) the same number of protons and a different number of neutrons.
(b) the same number of neutrons and a different number of protons.
(c) the same number of protons and a different number of electrons.
(d) the same number of electrons and a different number of protons.
33. Some isotopes of some elements are unstable; the nuclei of these atoms break apart and release high energy
particles into their surroundings. Such isotopes are said to be
(a) excited. (b) charged. (c) subatomic. (d) radioactive.
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34. Protium, deuterium, and tritium are three isotopes of
(a) hydrogen. (b) carbon. (c) oxygen. (d) water.
Science 9
TEST: Chapter 3 M odels For Atoms
Page 4 of 4
II. Short Answer. (15 points) Do all your work on this paper.
/3
1. Circle the word in brackets that best completes each blank.
• Atomic number refers to the number of (a)_____ (protons; neutrons; electrons; protons+neutrons) in an atom.
• Every element has a unique number of (b)_____ (protons; neutrons; electrons;protons+neutrons) in its atoms or ions.
• The atom represented by cobalt-60 has 60 (c)_____ (protons; neutrons; electrons; protons+neutrons), 33 (d)_____
(protons; neutrons; electrons; protons+neutrons), 27 (e)_____ (protons; neutrons; electrons; protons+neutrons), and
27 (f)_____ (protons; neutrons; electrons; protons+neutrons)
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2.
W rite down the number of protons, neutrons, and electrons in each of the following atoms.
(a) 2 2 Ne = __ p, __ n, __ e (b) 6 4 Cu = __ p, __ n, __ e
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3.
Anywhere in the space at right, write standard atomic notation for the following atoms.
(a) an oxygen atom with 10 neutrons and 8 protons
(b) the atom with atomic number 26 and mass number 54
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4.
Anywhere in the space ar right, draw Bohr or Bohr-Rutherford diagrams for any 2 of the following:
(a) fluorine, atomic number 9, symbol F
(b) silicon, atomic number 14, symbol Si
(c) potassium, atomic number 19, symbol K
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5.
Chlorine consists of two isotopes: chlorine-35 and chlorine -37 (also shown as 3 5 Cl and
sentences/paragraphs to answer the following.
(a) Describe what is similar about these two isotopes.
(b) Describe what is different about the two isotopes.
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4.
Complete the blanks in the following table.
atom/ion
symbol
atomic
number
mass number
9
19
protons
Cl). W rite complete
neutrons
18
21
56
35
charge
0
20
Fe
electrons
37
+3
36
45
Part I @ 30 points + Part II @ 15 points = 45 points total
BONUS! – Discuss/explain as many things as possible about how the Periodic Table is laid out; what information can be
obtained from it, etc. (Use the back of this page.)