Name: 
 

Atoms & Molecules



Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 

1. 

A student finds a sample of a clear, colourless, odourless liquid in the science laboratory. With his teacher's permission, he decides to measure the boiling point of the liquid, and finds it to be 106 degrees C. Based on that observation, what is a reasonable conclusion for the student to reach?
a.
The liquid is probably water.
c.
The liquid is not pure water.
b.
The thermometer was faulty.
d.
He heated the liquid too quickly.
 

2. 

All of the following are properties of magnesium. Identify the physical property.
a.
Magnesium burns in air with a brilliant white flame.
b.
Magnesium reacts with hydrochloric acid to produce a gas.
c.
Magnesium is a good conductor of electricity.
d.
Magnesium combines with nitrogen to form a black powder.
 

3. 

Which property is described by the statement that aluminum can be bent into various shapes?
a.
density
c.
hardness
b.
malleability
d.
viscosity
 

4. 

Diamond can scratch glass. Which property of both substances is described by this statement?
a.
ductility
c.
hardness
b.
crystal form
d.
density
 

5. 

Which physical property is described by the statement that copper can be drawn into fine wires?
a.
density
c.
viscosity
b.
hardness
d.
ductility
 

6. 

The liquid state of matter has
a.
an indefinite shape and a definite volume.
b.
a definite shape and a definite volume.
c.
an indefinite shape and an indefinite volume.
d.
a definite shape and an indefinite volume.
 

7. 

One of the physical properties of matter that you read about is viscosity. This term is usually used to describe oils used in automobile engines. If oil A is more viscous than oil B, then this means that
a.
oil A is thinner than oil B.
b.
oil A is thicker than oil B.
c.
oil A is a more expensive oil than oil B.
d.
oil A is more soluble in water than oil B.
 

8. 

Identify the chemical change in the following:
a.
the crushing of stones
c.
the separation of cream from milk
b.
the formation of clouds
d.
the burning of a candle
 

9. 

An example of a physical change is
a.
toasting a piece of bread.
c.
boiling oil.
b.
the explosion of dynamite.
d.
the rusting of iron.
 

10. 

Which one of the following is an example of a physical change?
a.
baking a cake
c.
bleaching a stain in clothes
b.
cutting paper into strips
d.
food digesting in your stomach
 

11. 

A physical change in a substance
a.
changes the form or state of the substance.
b.
results in a change in the mass of the substance.
c.
changes it into a different substance.
d.
is usually very hard to reverse.
 

12. 

Matter can exist in one of three states. These are
a.
physical, chemical, metal.
c.
reactant, product, precipitate.
b.
alloy, crystal, hydrocarbon.
d.
solid, liquid, gas.
 

13. 

When some solid mothballs are placed in a clothes closet, they gradually disappear over a period of time. The change of state that occurs is
a.
evaporation.
c.
condensation.
b.
sublimation.
d.
melting.
 

14. 

Iron is widely used to build cars, bridges, and buildings. One of the major problems with iron is that it rusts under certain conditions. The reaction of iron to form rust is called
a.
combustion.
c.
a physical change.
b.
precipitate.
d.
corrosion.
 

15. 

Several methods are used to prevent or slow the rusting of iron. Which of the following is not likely to be used for this purpose?
a.
spraying water on the iron
b.
attaching another metal that reacts with oxygen faster than iron reacts
c.
covering the iron with a coating of oil
d.
covering the iron by painting it
 

16. 

When a hydrocarbon such as coal, natural gas, or oil burns, the products are most likely to be
a.
carbon and oxygen.
c.
hydrogen and carbon.
b.
hydrogen and water.
d.
carbon dioxide and water.
 

17. 

The fire triangle is a useful way of remembering the components of a combustion reaction. The three parts of the triangle are
a.
heat, fuel, oxygen.
c.
light, fuel, oxygen.
b.
heat, fuel, hydrogen.
d.
reactants, products, fossil fuels.
 

18. 

All of the following statements are part of the particle theory of matter except one. Identify the exception.
a.
Different substances are made of different particles.
b.
The particles in solids are harder than the particles in liquids.
c.
The particles are always moving.
d.
There are forces of attraction between the particles.
 

19. 

Which one of the following statements about the particles in a piece of silver is incorrect?
a.
All of the particles have the same mass.
b.
The particles are always moving.
c.
There are strong forces of attraction between the particles.
d.
As the temperature increases, the particles move more slowly.
 

20. 

The particle theory of matter is a useful scientific model because
a.
it proves that matter is made of particles.
b.
it allows scientists to explain many of the properties of matter.
c.
it is easy to understand.
d.
it was developed by famous scientists.
 

21. 

Air is classified as a mixture because
a.
it is clear and colourless.
b.
it contains at least two different pure substances.
c.
its composition never changes.
d.
its major components are elements.
 

22. 

Only one of the following statements is correct. Identify that statement.
a.
All compounds consist of two or more elements.
b.
All pure substances are elements.
c.
All mixtures are solutions.
d.
All solutions are heterogeneous.
 

23. 

Substances composed of identical atoms are
a.
mixtures.
c.
compounds.
b.
elements.
d.
solutions.
 

24. 

Scientists have been able to identify about 110 elements and a few million compounds. How many different kinds of atoms are there?
a.
About 110.
b.
A few million.
c.
Two.
d.
It's impossible to tell from the information given.
 

25. 

Only one of the following statements about molecules is correct. Which one?
a.
All molecules consist of two atoms joined together.
b.
All molecules consist of identical atoms joined together.
c.
Molecules cannot be split apart.
d.
All water molecules consist of two hydrogen atoms and one oxygen atom.
 

26. 

Which one of the following substances is an element?
a.
Water
c.
Helium
b.
Salt
d.
Milk
 

27. 

Silicon dioxide, SiO2, is the major component of sand. Silicon dioxide is considered to be a compound because
a.
it is a pure substance.
c.
it is a very common substance.
b.
it consists of two different elements.
d.
its composition varies.
 

28. 

The total number of atoms represented by the formula K2Cr2O7 is
a.
1.
c.
11.
b.
3.
d.
28.
 

29. 

Which of the following gases is not a component of our atmosphere?
a.
hydrogen
c.
carbon dioxide
b.
nitrogen
d.
argon
 

30. 

Carbon dioxide and carbon monoxide are compounds made up of the elements carbon and oxygen. Based on that information only, which of the following statements is most likely correct?
a.
The two compounds have different properties.
b.
Carbon dioxide is a gas and carbon dioxide is a liquid.
c.
The two compounds have the same properties.
d.
One compound is more poisonous than the other.
 

31. 

Ozone is an important gas in the upper part of our atmosphere because
a.
it traps heat, thus keeping our planet warmer.
b.
it filters out damaging ultraviolet radiation.
c.
it prevents gases from the Sun from reaching Earth.
d.
it reduces the pollution caused by fossil fuels.
 

32. 

For hundreds of years up to about A.D.1600, a group of people called alchemists carried out thousands of experiments and invented many pieces of laboratory equipment that we still use today. The major goal of the alchemists was to
a.
find evidence for the existence of atoms.
b.
turn gold into iron or lead.
c.
turn metals such as iron and lead into gold.
d.
prove that fire, earth, air, and water were elements.
 

33. 

Which 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.
 

34. 

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.
 

35. 

Which scientist first proposed the existence of the nucleus in atoms?
a.
Rutherford
c.
Thomson
b.
Bohr
d.
Dalton
 

36. 

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.
 

37. 

According to the Rutherford model of the atom, most of the space that an atom takes up consists of
a.
protons.
c.
neutrons.
b.
a nucleus.
d.
empty space.
 

38. 

Several models of the atom have been suggested by scientists since the beginning of the nineteenth century. What is the correct chronological order (earliest to latest) of the models proposed by the scientists listed below?
a.
Dalton, Bohr, Thomson, Rutherford
c.
Thomson, Dalton, Rutherford, Bohr
b.
Dalton, Thomson, Rutherford, Bohr
d.
Dalton, Rutherford, Thomson, Bohr
 

39. 

One model of the atom is sometimes referred to as the "raisin bun" model. In this model, the raisins represent the
a.
protons.
c.
nucleus.
b.
neutrons.
d.
electrons.
 

40. 

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.
 

41. 

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.
 

42. 

The positively charged particles found in the nucleus of an atom are
a.
electrons.
c.
neurons.
b.
neutrons.
d.
protons.
 

43. 

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.
 

44. 

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.
 

45. 

The particles that make up most of the mass of an atom are
a.
the protons and electrons.
c.
the protons and neutrons.
b.
the neutrons and electrons.
d.
only the neutrons.
 

46. 

The numbers of protons, electrons, and neutrons in an atom of 144Cs are
a.
55 protons, 55 electrons, 144 neutrons.
b.
55 protons, 55 electrons, 89 neutrons.
c.
89 protons, 89 electrons, 144 neutrons.
d.
55 protons, 89 electrons, 89 neutrons.
 

47. 

The symbol Cl represents an atom with
a.
17 protons, 20 electrons, 20 neutrons.
c.
20 protons, 20 electrons, 17 neutrons.
b.
17 protons, 17 electrons, 17 neutrons.
d.
17 protons, 17 electrons, 20 neutrons.
 

48. 

An atom with an atomic number of 38 and a mass number of 88 contains
a.
50 neutrons.
c.
38 neutrons.
b.
50 electrons.
d.
88 protons.
 

49. 

In Bohr's planetary model of the atom, he suggested that
a.
electrons could be found only in certain orbits or energy levels.
b.
the closer an electron is to the nucleus, the higher its energy.
c.
electrons always stay in the same energy level.
d.
the orbit closest to the nucleus can hold eight electrons.
 

50. 

The number of electrons in the outermost orbit of a phosphorus atom is
a.
2.
c.
5.
b.
8.
d.
15.
 

51. 

An atom can form a positive ion by
a.
losing electrons.
c.
losing protons.
b.
gaining electrons.
d.
gaining protons.
 

52. 

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.
 

53. 

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.
 

54. 

When compounds containing certain metals are placed in a flame, different flame colours are produced. For example, sodium compounds always produce yellow flames. The reason that this happens is because
a.
all atoms of the metal have the same mass.
b.
all atoms of the metal have the same symbol.
c.
all atoms of the metal have the same number of neutrons.
d.
all atoms of the metal have the same electron arrangement.
 

55. 

Mendeleev is sometimes referred to as "the father of the periodic table." He knew some of the properties of about 64 elements, and by arranging the elements in a certain way, he formed a table in which elements with similar properties appeared in the same column. To produce this table, Mendeleev arranged the known elements in order of
a.
increasing atomic number.
c.
increasing atomic mass.
b.
increasing atomic size.
d.
the dates of discovery of the elements.
 

56. 

Which group in the periodic table contains the noble gases?
a.
1
c.
17
b.
15
d.
18
 

57. 

Which of the following groups of elements contains only metalloids?
a.
Ge, As, Sb, Te
c.
Ge, As, Sb, Bi
b.
Li, Na, K, Rb
d.
Ge, Pb, Au, Ag
 

58. 

The reason for the chemical similarity among elements of a given group in the periodic table is the
a.
similarity in the highest orbit electrons.
b.
similarity in their nuclear structure.
c.
fact that they all have the same number of protons.
d.
fact that they all have the same number of neutrons.
 

59. 

Chemists believe that the chemical properties of an element are directly related to the
a.
number of neutrons in the nucleus of an atom.
b.
atomic mass of an atom.
c.
electrons in the outermost of an atom.
d.
the mass number of the atom.
 

60. 

Moving down a column in the periodic table, the number of electrons in the highest orbit
a.
increases gradually.
c.
shows no pattern.
b.
decreases gradually.
d.
remains constant.
 

61. 

Which element in the following list is a member of the noble gases?
a.
francium
c.
astatine
b.
aluminum
d.
radon
 

62. 

Which of the following elements would you expect to react in a manner most similar to nitrogen?
a.
phosphorus (P)
c.
neon (Ne)
b.
sodium (Na)
d.
oxygen (O)
 

63. 

The group 1 elements are similar in that they
a.
are all very unreactive.
b.
all form ions with a charge of 2+.
c.
all have one more electron than the noble gases.
d.
all have one less electron than the noble gases.
 

64. 

Two elements X and Y (not their symbols) are members of the same family of elements. It can therefore be concluded that the elements have the same
a.
atomic radius.
c.
number of outer-level electrons.
b.
atomic mass.
d.
physical state at room temperature.
 

65. 

Only one of the following elements is correctly described. Which one?
a.
Element 11 is an alkali metal in period 2.
b.
Element 17 is a halogen in period 17.
c.
Element 18 is a noble gas in period 3.
d.
Element 20 is a precious metal in period 2.
 

66. 

The noble gases are very unreactive because
a.
they are very rare.
c.
they have very low densities.
b.
their outer orbits are filled.
d.
they have low boiling points.
 

67. 

Argon gas is used to fill ordinary lightbulbs. The property of argon that makes it useful for this purpose is that argon
a.
is a very good conductor of electricity.
b.
is a very unreactive gas.
c.
is a good conductor of heat.
d.
reacts with the metal in the bulb to produce light.
 

68. 

The most reactive elements in the periodic table are found in
a.
groups 1 and 18.
c.
groups 3 and 4.
b.
groups 2 and 15.
d.
groups 1 and 17.
 

69. 

Rows in the periodic table are also referred to as
a.
periods.
c.
groups.
b.
families.
d.
columns.
 

70. 

All members of this group of elements form ions with a +1 charge when they react. What group is this?
a.
Noble gases
c.
Metalloids
b.
Halogens
d.
Alkali metals
 

71. 

All members of this group of elements form ions with a -1 charge when they react. What group is this?
a.
Noble gases
c.
Metalloids
b.
Halogens
d.
Alkali metals
 

72. 

A new element is discovered and scientists are able to show that its atomic number is 116. Based on your knowledge of the periodic table, how many electrons is an atom of this element likely to have in its highest orbit?
a.
8
c.
2
b.
16
d.
6
 

73. 

The least reactive element in the following list is
a.
argon.
c.
potassium.
b.
gold.
d.
copper.
 

74. 

Which of the following statements concerning the halogens is correct?
a.
An iodine atom is larger than a bromine atom because iodine has a higher melting point.
b.
An iodine atom is larger than a bromine atom because iodine has more orbits.
c.
Fluorine is the least reactive of the halogens.
d.
All halogen atoms have six electrons in their outer orbits.
 

75. 

Gallium is the element immediately under aluminum in the periodic table in group 13. Based on this information, how many electrons is a gallium atom likely to lose or gain to form a stable ion?
a.
13
c.
2
b.
3
d.
1
 

Matching
 
 
Match the following scientists with their contributions to our knowledge of the structure of the atom.
a.
Bohr
c.
Dalton
b.
Rutherford
d.
Thomson
 

76. 

All elements are made up of atoms, which are like tiny indivisible spheres; different elements have different atoms.
 

77. 

At the centre of the atom is a very small, extremely dense, positively charged region called the nucleus.
 
 
The following diagrams represent the atomic models proposed by Dalton, Thomson, Rutherford, and Bohr. Match the correct names with each diagram.
a.
chem_test_files/i0810000.jpg
c.
chem_test_files/i0810001.jpg
b.
chem_test_files/i0810002.jpg
d.
chem_test_files/i0810003.jpg
 

78. 

Thomson
 

79. 

Dalton
 

80. 

Rutherford
 



 
Check Your Work     Reset Help