Preview Extract
Chapter 15 How Atoms Bond and Molecules Attract
15.1 Electron-Dot Structures
1) What is the valence shell?
A) It is the outermost shell of electrons in an atom.
B) It is the shell of electrons in an atom that is the least reactive.
C) It is the last partially filled orbital in an atom.
D) It is the shell of electrons in element V (atomic no. = 23)
E) It is the same as the orbital configuration.
Answer: A
2) The concept of a chemical bond is ________.
A) how two or more atoms are held together
B) the sharing of nucleons
C) how two or more electrons reside in an orbital
D) how much energy it takes to remove an electron from a set of atoms
E) none of the above
Answer: A
3) Many of the macroscopic properties of a compound depend on ________.
A) how the atoms of the molecules are held together
B) the mass of the constituent atoms
C) the number of nucleons present in the sample
D) the size of the sample
E) how the atoms absorb light and the shape of the orbitals
Answer: A
4) Which of the following is the correct electron dot structure for chlorine (atomic no. = 17)?
A) a
B) b
C) c
D) d
E) e
Answer: D
5) Which of the following is the correct electron dot structure for carbon (atomic no. = 6)?
A) a
B) b
C) c
D) d
E) e
Answer: E
6) Which of the following has the greatest number of nonbonding pairs of electrons ?
A) C
B) H
C) He
D) F
E) S
Answer: D
7) How many valence electrons does boron (B, atomic no. = 5) have?
A) 1
B) 2
C) 3
D) 4
E) 5
Answer: C
8) How many valence electrons does gallium (Ga, atomic no. = 31) have?
A) 1
B) 6
C) 3
D) 31
E) 70
Answer: C
9) How many valence electrons does bromine (Br, atomic no. = 35) have?
A) 1
B) 7
C) 21
D) 28
E) 35
Answer: B
10) Which of the following elements has six valence electrons?
A) Be
B) B
C) C
D) N
E) O
Answer: E
11) Which of the following elements has two valence electrons?
A) Na
B) Mg
C) H
D) Ne
E) Li
Answer: B
12) What is one role of unpaired valance electrons?
A) They take part in the formation of different types of bonds.
B) They keep the paired electrons separated to minimize interaction.
C) They are the nonbonding electrons.
D) They provide the number of Lewis dots.
E) They tell us which Lewis dot structure is correct.
Answer: A
13) How do the electron-dot structures of elements in the same group in the periodic table
compare with one another?
A) The structures differ by exactly two electrons between vertically consecutive elements.
B) The number of valence shell electrons increases by one for each element from the top to the
bottom of the group.
C) Elements of the same group have the same number of valence electrons.
D) The number of electrons in the electron-dot-structure will equal the group number for each
element of the group.
Answer: C
14) How many more electrons can fit within the valence shell of a hydrogen atom?
A) 1
B) 2
C) 7
D) 0
Answer: A
15) How is the number of unpaired valence electrons in an atom related to the number of bonds
that the atom can form?
A) There is no defined relationship between the number of unpaired valence electrons and
number of bonds that the atom can form.
B) The number of unpaired valence electrons in an atom is one-half the number of bonds that the
atom can form.
C) The number of unpaired valence electrons in an atom is twice the number of bonds that the
atom can form.
D) The number of unpaired valence electrons in an atom is the same as the number of bonds that
the atom can form.
Answer: D
15.2 The Formation of Ions
1) Why is it so easy for a magnesium atom to lose two electrons?
A) The nuclear charge of the magnesium atoms is relatively weak.
B) These two electrons are found relatively far from the nucleus.
C) These two electrons are well shielded from the nuclear charge.
D) There are lots of electron-electron repulsions that go on within the valence shell.
Answer: C
2) An atom loses an electron to another atom. Is this an example of a physical or chemical
change?
A) physical change involving the formation of negative ions
B) chemical change involving the formation of neutral atoms
C) physical change involving the formation of positive ions
D) chemical change involving the formation of ions
Answer: D
3) How is it possible for a neutral molecule, such as water, to form an ion?
A) It can combine with a hydrogen ion to form a positively charged species.
B) It can combine with a chloride ion to form a negatively charged species.
C) It can fragment into protons and electrons.
D) It can absorb electrons and become negatively charged.
E) It can absorb electrons and become positively charged.
Answer: A
4) If carbonic acid (H2CO3) were to undergo ionization, what would one of the products be?
-
A) H
B) CO2
C) H2O
D) CO3
E) CO3
-1
-2
Answer: E
5) What is the name for the following polyatomic ion?
CH3CO2
-1
A) acetate
B) monocarboxylate
C) carboxylic
D) acidic
E) acetic
Answer: A
6) What is the name for the following polyatomic ion?
PO4
-3
A) phosphate
B) phosphorus oxide
C) phosphinate
D) trioxo phosphoride
E) potassium
Answer: A
7) Which of the following elements will most likely not form an ion at all?
A) Na
B) O
C) Ar
D) Mg
E) Br
Answer: C
8) Which of the following elements will most likely form an ion with a -1 charge?
A) Na
B) S
C) Ne
D) Mg
E) Cl
Answer: E
9) Which of the following elements will most likely form an ion with a -2 charge?
A) Na
B) S
C) Ne
D) Mg
E) Cl
Answer: B
10) Which of the following elements will most likely form an ion with a + 2 charge?
A) Na
B) Mg
C) Ne
D) Si
E) Cl
Answer: B
11) Which of the following elements will most likely form an ion with a + 1 charge?
A) Na
B) Mg
C) Al
D) Si
E) Cl
Answer: A
12) Which of the following would be an ion with a double positive charge?
A) an Mg atom that gains two electrons
B) an Mg atom that gains one electron
C) an Mg atom that loses two electrons
D) an Mg atom that loses one electron
E) none of the above
Answer: C
13) Which of the following would be a negative ion with a single charge?
A) an atom with 11 protons and 12 electrons
B) an atom with 11 protons and 11 electrons
C) an atom with 12 protons and 11 electrons
D) an atom with 10 protons and 12 electrons
E) none of the above
Answer: A
14) Which of the following is a negative ion?
+1
A) Na
B) Na
-2
C) O
D) O
E) all of the above
Answer: C
15) Which of the following is a positive ion?
+1
A) Na
B) Ca
+2
C) Mg
D) Al
+2
+3
E) all of the above
Answer: E
-3
16) What needs to be done to convert a neutral nitrogen atom into an N species?
A) add three electrons
B) remove three electrons
C) remove three protons
D) add three protons
E) add three nitrogens
Answer: A
17) If a neutral atom gains two electrons, what is the electrical charge of the atom?
A) -1
B) +1
C) -2
D) +2
E) neutral
Answer: C
18) If a neutral atom loses one electron, what is the electrical charge of the atom?
A) -1
B) +1
C) -2
D) +2
E) neutral
Answer: B
19) Which of the following is an ion?
A) 2 H2
B) Br2
C) HCl
D) Au + 3 Br2
E) none of the above
Answer: E
20) Which of the following is NOT an ion?
+1
A) H
B) Br
-
C) O2
D) Mg
+2
E) NO3
-
Answer: C
21) The neon atom tends NOT to lose any electrons because
A) of its relatively strong effective nuclear charge.
B) that would result in a negative ion.
C) its electrons are paired together within the same orbitals.
D) the ionization energy is so high.
Answer: A
22) The neon atom tends NOT to gain any additional electrons because
A) its nuclear charge is not great enough.
B) that would result in a positive ion.
C) of the repulsions they would experience with electrons in the same shell.
D) there is no more room available in its outermost occupied shell.
Answer: D
23) Why doesn't the sodium atom gain seven electrons so that its third shell becomes the filled
outermost shell?
A) It would be too difficult for another atom to lose seven electrons.
B) Only six additional electrons are required to fill the outermost shell of sodium.
C) In gaining seven more electrons, sodium's fourth outer shell becomes filled.
D) Sodium's nuclear charge is not strong enough to hold that many more electrons.
Answer: D
24) Which should be larger, the potassium atom, K, or the potassium ion, K⁺?
A) The potassium ion, K⁺ is larger since charging an atom always makes it larger.
B) The potassium atom, K, with an additional shell of electrons is larger.
C) The potassium ion, K⁺ is larger since it has an extra electron which increases its size.
D) The potassium atom and the potassium ion are exactly the same size and only differ in charge.
Answer: B
25) Why does an atom with many valence electrons tend to gain electrons rather than lose any?
A) Atoms with many valence electrons tend to have relatively weak forces of attraction between
the valence electrons and the nucleus. Therefore, the outer electrons are free to attract other
electrons.
B) There is stability in numbers. Atoms with many valence electrons are always attracting new
electrons.
C) The old adage that "he who has, gets" is also True in atomic structure. Atoms with many
valence electrons can essentially overpower atoms with few valence electrons and attract
additional electrons.
D) Atoms with many valence electrons tend to have relatively strong forces of attraction between
the valence electrons and the nucleus. This makes it easy for them to gain additional electrons.
Answer: D
26) Take money away from your bank account and the bank will show a negative credit. Take an
electron away from an atom, however, and the atom shows up positive. Explain.
A) Electrons are already negative. Therefore, we know from basic math that subtracting a
negative (number) from a neutral (atom), will make the result positive.
B) Neutral atoms contain identically charged but oppositely signed protons and electrons.
Removing one of the negative electrons results in an excess of positively charged protons.
C) Removing an electron from an atom does not have the atom show up positive. It simply
leaves the atom short one electron.
D) Atoms are constantly exchanging electrons. Having an atom "show up positive" is only an
expression indicating that it has taken its turn in the game of electron exchange.
Answer: B
15.3 Ionic Bonds
1) Which of the following best describes ionic bonding?
A) two atoms sharing a set of electrons
B) two atoms exchanging a set of electrons
C) one atom giving up some of its electrons to another atom
D) when two elements with same charge are held together by electrostatic forces
E) none of the above
Answer: C
2) Which of the following molecules contains an ionic bond?
A) MgCl2
B) Cl2
C) SF3
D) PO4
-3
E) none of the above
Answer: A
3) If the following generic atom were to undergo ionization, what would the most likely product
be?
A) +1
B) -2
C) -3
D) +4
E) would probably not ionize
Answer: E
4) If the following generic atom were to undergo ionization, what would be the charge of the
most likely product?
A) +2
B) -2
C) -6
D) +6
E) would probably not ionize
Answer: A
5) If the following generic atom were to undergo ionization, what would be the charge of most
likely product?
A) +3
B) -3
C) -5
D) 8
E) would probably not ionize
Answer: B
6) What is the compound that forms if you react potassium and sulfur?
A) K2S
B) KS
C) SP
D) PS2
E) SkP
Answer: A
7) If you mix a typical aluminum ion (Al, atomic no. = 13) with a typical oxygen ion (O, atomic
no. = 8), what compound is formed?
A) Al2O3
B) Al3O2
C) Al13O8
D) Al3O
E) Al2O2
Answer: A
8) If you mix a typical iodine ion (I, atomic no. = 53) with a typical barium ion (Ba, atomic no. =
56), what compound is formed?
A) BaI2
B) BaI
C) Ba56I53
D) Ba2I
E) Ba2I2
Answer: A
-2
+4
9) How many oxide ions (O ) are needed to balance the positive charge of a titanium ion (Ti )?
A) 2
B) 1
C) 3
D) 4
E) 6
Answer: A
-1
10) How many chloride ions (Cl ) are needed to balance the positive charge of a barium ion
+2
(Ba )?
A) 2
B) 1
C) -2
D) -1
E) 3
Answer: A
11) Which are closer together: the two nuclei within potassium fluoride, KF, or the two nuclei
within molecular fluorine, F2?
A) KF
B) F2
C) Both are the same. Any atom bonded to F will have the same inter-nuclear separation.
D) It makes little sense to compare two molecules which exist in different physical states. KF is a
solid while F2 is a gas.
Answer: B
12) Which would you expect to have a higher melting point: sodium chloride, NaCl, or
aluminum oxide, Al2O3?
A) The aluminum oxide has a higher melting point because it is a larger molecule and has a
greater number of molecular interactions.
B) NaCl has a higher melting point because it is a solid at room temperature.
C) The aluminum oxide has a higher melting point because of the greater charges of the ions, and
hence the greater force of attractions between them.
D) The aluminum oxide has a higher melting point because of the covalent bonds within the
molecule.
Answer: C
13) Is an ionic compound an example of a chemical compound, or is a chemical compound an
example of an ionic compound?
A) An chemical compound is an example of a ionic compound.
B) Neither is an example of the other.
C) Each is an example of the other.
D) An ionic compound is an example of a chemical compound.
Answer: D
14) What molecule loses a proton to form the hydroxide ion, OH⁻?
A) The oxygen molecule, O2
B) The water molecule, H2O
C) The hydrogen peroxide molecule, H2O2
D) The hydrogen molecule, H2
Answer: B
15) Barium ions carry a 2+ charge, and nitrogen ions carry a 3-charge. What would be the
chemical formula for the ionic compound barium nitride?
A) Ba3N2
B) Ba2N3
C) Ba3N4
D) Ba2N2
Answer: A
16) Magnesium ions carry a 2+ charge, and chloride ions carry a 1- charge. What is the chemical
formula for the ionic compound magnesium chloride?
A) MgCl
B) Mg2Cl
C) MgCl2
D) Mg2Cl2
Answer: C
17) Which of the following compounds contains ionic bonds?
A) CH4
B) K2O
C) Cl2
D) OF2
E) none of the above
Answer: B
-
18) Which of the following substances contains F ions?
A) PF3
B) F2
C) CF4
D) CaF2
E) all of the above
Answer: D
19) Which of the following does not describe ionic compounds?
A) They have a tendency to melt easily.
B) They consist of positive and negative ions.
C) They are held together by electrostatic attraction.
D) They are usually very ordered.
E) none of the above
Answer: A
20) Which would you expect to have a higher melting point: sodium chloride, NaCl, or cesium
chloride, CsCl? Why?
A) The cesium chloride has a higher melting point because larger ions of the same charge are
able to attract more ions of the opposite charge.
B) The cesium chloride has a higher melting point because its ions are smaller, which makes the
charges more dense.
C) The sodium chloride has a higher melting point because of the greater charges of the ions, and
hence the greater force of attractions between them.
D) The sodium chloride has a higher melting point because its ions are smaller, which allows
oppositely charged ions to get closer.
Answer: D
21) MgCl2 crystals are composed of
A) units of MgCl2 molecules held together by dipole interactions.
2+
B) groups of Mg ions and Cl2 molecules.
C) units composed of six Mg atoms and six Cl2 molecules.
2+
D) a multitude of Mg ions and
2+
1:2 ratio of Mg to
ions grouped together in a three-dimensional array with a
.
E) a two-dimensional array of [-Mg-Cl-Cl-] units.
Answer: D
15.4 Metallic Bonds
1) Which of the following is not a property of metal?
A) does not conduct heat well
B) conducts electricity
C) is shiny
D) is strong, but can be bent
E) All of the above are properties of metals.
Answer: A
2) Metals are useful for the structural support of buildings because they
A) do not conduct heat well
B) are shiny
C) conduct electricity
D) are strong but can be bent
E) C and D
Answer: D
3) Metals are often used for making designer jewelry because they
A) do not conduct heat well
B) conduct electricity
C) are shiny
D) are strong but can be bent
E) C and D
Answer: E
4) What property of metal atoms account for many of the observed bulk phenomena seen in
metal samples?
A) Metal atoms easily lose one or more outer electrons.
B) Metal atoms easily gain one or more outer electrons.
C) Metals readily form ionic bonds.
D) Metals readily form covalent bonds.
E) none of the above
Answer: A
5) Which of the following describes how a metal atoms behaves in a bulk metallic object?
A) The metal ion shares its outermost electrons freely with its neighbors.
B) The metal atoms have limited interaction with neighboring atoms.
C) The metal atom shares its electrons in a very directional manner.
D) The metal atom shares its electrons with only one other atom.
E) none of the above
Answer: A
6) Given that the total number of atoms on our planet remains fairly constant, how is it ever
possible to deplete a natural resource such as a metal?
A) The problem remains that not everyone recycles as they should.
B) Recycling only forestalls the inevitable depletion of metal resources.
C) The atoms don't leave our planet, which is why naturally occurring materials never really
reach the point of depletion.
D) The problem is with the expense of collecting metal atoms that are uniformly dispersed.
Answer: D
7) Distinguish between a metal and a metal-containing compound.
A) There is no distinction between the two.
B) Only one of these contains ionic bonds.
C) Only one of these contains covalent bonds.
D) Only one of these occurs naturally.
Answer: B
8) Why are ores so valuable?
A) They are sources of naturally occurring gold.
B) Metals can be efficiently extracted from them.
C) They tend to occur in scenic mountainous regions.
D) They hold many clues to Earth's natural history.
Answer: B
9) Why is it better to recycle metals than to mine more?
A) It takes far less energy to recycle.
B) Mining is less expensive than recycling but not environmentally friendly.
C) Ores contain toxic elements.
D) all of the above
E) none of the above
Answer: A
3
10) There is more gold in 1 km of the ocean than the amount of gold mined in all of recorded
history. How come we do not mine the oceans?
A) It is too dilute to separate.
B) It would take too much energy.
C) It would cost too much.
D) all of the above
E) none of the above
Answer: D
11) If the concentration of gold in seawater is 2.0 milligram per ton of sea water and the mass of
18
the ocean is 1.5 × 10 tons, how much gold is in the ocean?
12
A) 3.0 × 10 kg
B) 3.0 kg
C) 300 g
D) 36 mg
E) 3,000 lb
Answer: A
12) What property of alloys make them ideal for developing new materials?
A) The characteristics of the material change depending on how much of each component is
present.
B) Alloys are very rigid and are extremely resistant to chemical decomposition.
C) The size of the atoms involved is directly related the electrical conductivity.
D) all of the above
E) none of the above
Answer: A
13) Why is metal shiny?
A) The loose electrons reflect most wavelengths of light.
B) The electrons transmit most wavelengths of light.
C) The electrons absorb each light wave.
D) The electrons emit light due to electronic excitation.
E) all of the above
Answer: A
15.5 Covalent Bonds
1) What is a molecule?
A) a group of atoms that are held together by covalent bonds
B) a group of atoms that are held together by ionic bonds
C) pair of atoms sharing a set of valence electrons
D) pair of shared valence electrons
E) group of covalent compounds held together by ionic bonds
Answer: A
2) What it the main difference between an ionic and a covalent bond?
A) One is the sharing of a pair of electrons, the other is the transfer of at least one electron.
B) One involves electrons, the other does not involve any electrons.
C) The electrons in both types of bonding undergo an exchange.
D) The electrons are traded between the two atoms and this keeps the atoms close.
E) Both bonds are the same, but named different to describe different atoms involved.
Answer: A
3) What does the line in the following example actually represent?
H—H
A) a shared pair of electrons
B) a covalent bond
C) an ionic bond
D) a pair of nonbonding electrons
E) A and B
Answer: E
4) How many nonbonding pairs of electrons are in the following molecule?
H—H
A) 1 pair
B) 6 pairs
C) 0 pairs
D) 8 pairs
E) none of the above
Answer: C
5) How many covalent bonds would the following atom usually form?
A) 1
B) 2
C) 4
D) 6
E) It would tend to form ionic bonds.
Answer: E
6) How many covalent bonds would the following generic atom usually form?
A) 1
B) 2
C) 4
D) 8
E) would usually not form any covalent bonds
Answer: E
7) How many covalent bonds would the following atom usually form?
A) 3
B) 2
C) 1
D) 5
E) would usually not form any covalent bonds
Answer: A
8) Which of the following statements is unTrue?
A) Covalent molecules are never crystalline.
B) Covalent molecules usually have low melting points.
C) Covalent molecules can have nonbonding electrons.
D) Covalent bonds can involve more than one pair of electrons.
E) All of the above statements are True.
Answer: A
9) Classify the following bonds as ionic, covalent, or neither (O, atomic number 8; F, atomic
number 9; Na, atomic number 11; Cl, atomic number 17; U, atomic number 92).
A) covalent, ionic, covalent
B) ionic, covalent, neither
C) neither, ionic, covalent
D) covalent, ionic, neither
Answer: D
10) Which of the following substances is pure?
A) an ionic compound consisting of sodium and chlorine ions
B) a covalent compound consisting of one type of molecule
C) an element
D) all of the above
E) none of the above
Answer: D
15.6 Polar Covalent Bonds
1) Which of the following statements best describes a relatively polar bond?
A) a very electronegative atom and a weakly electronegative atom are covalently bound
B) two very electronegative atoms are covalently bound
C) two very electronegative atoms undergo ionic bonding
D) two weakly electronegative atoms undergo ionic bonding
E) none of the above
Answer: A
2) Which of the following molecules would contain a dipole?
A) H-F
B) Cl-Cl
C) H-H
D) F-F
E) all of the above
Answer: A
3) Which of the following molecules contains a polar bond?
A) H-F
B) Cl-Cl
C) H-H
D) F-F
E) all of the above
Answer: A
4) Which of the following bonds would be the most polar?
A) C-F
B) C-Cl
C) C-Br
D) C-I
E) All are equally polar.
Answer: A
5) Which of the following bonds would be the least polar?
A) C-F
B) C-O
C) C-Cl
D) C-H
E) All are equally polar.
Answer: D
6) Which of the following compounds has polar covalent bonds?
A) H2O
B) CsF2
C) S8
D) Ne
E) CH4
Answer: A
7) Does an ionic bond have a dipole?
A) No, dipoles are only found in covalent compounds.
B) No, but the electrical charges are relatively strong.
C) Yes, the ionic bond is an example of a very strong dipole.
D) Yes, but for ionic compounds they are referred to as monopoles.
Answer: C
8) The source of an atom's electronegativity is the
A) repulsive force occurring among electrons within the same shell.
B) repulsive force occurring between electrons within neighboring shells.
C) positively charged atomic nucleus.
D) kinetic energy electrons have orbiting the nucleus.
Answer: C
9) In terms of the periodic table, is there an abrupt or gradual change between ionic and covalent
bonds?
A) There is an abrupt change that occurs across the metalloids.
B) Actually, any element of the periodic table can form a covalent bond.
C) There is a gradual change: the farther apart, the more ionic.
D) Whether an element forms one or the other depends on nuclear charge and not the relative
positions in the periodic table.
Answer: C
10) Atoms of nonmetallic elements form covalent bonds, but they can also form ionic bonds.
How is this possible?
A) This happens when one of the bonded nonmetallic elements has a strong electronegativity.
B) It happens when one of the nonmetallic elements loses an electron to become a positive ion.
C) An ionic bond results when a nonmetallic elements loses an electron to a metallic element.
D) An ionic bond results when a nonmetallic elements gains an electron from a metallic element.
Answer: D
11) Atoms of metallic elements can form ionic bonds, but they are not very good at forming
covalent bonds. Why?
A) These atoms are too large to be able to come in close contact with other atoms.
B) They have a great tendency to lose electrons.
C) Their valence shells are already filled with electrons.
D) They are on the wrong side of the periodic table.
Answer: B
12) Which bond is most polar?
A) H-N
B) N-C
C) C-C
D) O-H
Answer: D
13) Which is more polar, a sulfur-bromine (S-Br) bond or a selenium-chlorine (Se-Cl) bond?
A) A selenium-chlorine bond should be more polar because of a greater difference in effective
nuclear charge.
B) A selenium-chlorine bond should be more polar because of a smaller difference in effective
nuclear charge.
C) A sulfur-bromine bond should be more polar because of a greater difference in effective
nuclear charge.
D) A sulfur-bromine bond should be more polar because of a smaller difference in effective
nuclear charge.
Answer: A
15.7 Molecular Polarity
1) Which of the following molecules is polar?
A) a
B) b
C) c
D) All are polar.
E) Only A and C are polar.
Answer: C
2) Which of the above substances would have the lowest boiling point?
A) a
B) b
C) c
D) All boil at the same temperature.
E) All are gases.
Answer: A
3) Which of the above substances would have the largest dipole?
A) a
B) b
C) c
D) Each has the same size dipole.
E) None of the molecules has a dipole.
Answer: C
4) Which of the following molecules has the highest boiling point?
A) BH3
B) NH3
C) CH4
D) All of the above should have the same boiling point.
Answer: B
5) Which of the following statements describes a polar molecule?
A) The electrons in the molecule are distributed evenly throughout the molecule.
B) The molecules are usually not attracted to one another very strongly.
C) Polar molecules have the weakest intermolecular interactions with ionic compounds.
D) The molecules have a high degree of symmetry.
E) None of these statements describe polar molecules.
Answer: E
6) Which of the following molecules should have the same molecular shape and approximate
bond angles as ammonia, NH3 ?
A) BH3
B) CH4
C) SO3
D) PH3
E) NO2
Answer: D
7) Which molecule is most polar?
A) S=C=S
B) O=C=O
C) O=C=S
D) These all have the same polarity.
Answer: C
8) Which of the following molecules is the most polar?
A) HCl
B) BrF
C) CO
D) Br2
Answer: A
9) List the following bonds in order of increasing polarity:
A) N-O < N-N < N-F < H-F
B) N-N < N-O < N-F < H-F
C) H-F < N-F < N-O < N-N
D) N-N < N-O < H-F < N-F
Answer: B
10) Water, H2O, and methane, CH4, have about the same mass and differ by only one type of
atom. Why is the boiling point of water so much higher than that of methane?
A) The water molecule is less symmetrical than is the methane molecule.
B) The oxygen of a water molecule has two lone pairs of electrons.
C) The electronegativity difference between oxygen and hydrogen is greater than the
electronegativity difference between carbon and hydrogen.
D) all of the above
Answer: D
11) An individual carbon-oxygen bond is polar. Yet carbon dioxide, CO2, which has two carbonoxygen bonds, is nonpolar because
A) the molecule has an even number of electrons.
B) it has a greater symmetry.
C) the electron-pulls of the two oxygen atoms are equal and opposite.
D) Two of the above are reasonable.
Answer: D
12) A substance consisting of which molecule shown below should have a higher boiling point?
A) The molecule on the left, COCl2, because it has a fewer number of atoms.
B) The molecule on the right, C2H2Cl, because it has a greater number of atoms.
C) The molecule on the left, COCl2, because it is less symmetrical.
D) The molecule on the right, C2H2Cl, because of electronegativity considerations.
Answer: D
13) Ammonia, NH3, is more polar than is borane, BH3 because it
A) has a lone pair of electrons.
B) is less symmetrical than borane.
C) its hydrogens are not exactly opposite one another.
D) all of the above
Answer: D
15.8 Molecular Attractions
1) Which of the following is the weakest?
A) A chemical bond
B) An ion-dipole attraction
C) A dipole-dipole attraction
D) A dipole-induced dipole attraction
E) An induced dipole-induced dipole attraction
Answer: E
2) Which of the following is the strongest?
A) A chemical bond
B) An ion-dipole attraction
C) A dipole-dipole attraction
D) A dipole-induced dipole attraction
E) An induced dipole-induced dipole attraction
Answer: A
+
3) Which of the following molecules would you expect to be the least attracted to a Na ion?
A) H-F
B) H3C-CH3
C) Cl2CH2
D) F
-
E) HO
-
Answer: B
4) Which of the following molecules would you expect to be the most strongly attracted to a Cl
ion?
A) H-F
B) H3C-CH3
C) Cl-Cl
D) F-F
E) CCl4
Answer: A
5) The separation of charges within a polar molecule is called a(n) ________.
A) dipole
-
B) dipole-dipole
C) ionic bond
D) strong attraction
E) polar bond
Answer: A
6) What is happening at the molecular level when a polar molecule like water interacts with a
typical sodium ion?
A) The water molecule aligns such that the oxygen interacts with the sodium.
B) The water molecule aligns such that the hydrogens interact with the sodium.
C) The polarity of the water molecule is altered making the oxygen more positively charged.
D) The polarity of the water molecule is altered making the hydrogens more negatively charged.
E) none of the above
Answer: A
7) If an ionic bond is stronger than a dipole-dipole interaction, how can water dissolve an ionic
compound?
A) The ion-dipole interactions of a bunch of water molecules gang up on the strong ionic bond
and pull it into the solution.
B) The ionic bond is weakened by the ion-dipole interactions and ionic repulsion ejects the ions
from the crystal.
C) The ion-dipole interaction causes the ions to heat up and vibrate free of the crystal.
D) The ions never overcome their interatomic attraction and therefore are not soluble.
E) none of the above
Answer: A
8) What is the difference between a dipole-dipole interaction and an ion-dipole interaction?
A) one involves dipole attraction between neutral molecules while the other involves dipole
interactions with ions
B) one involves hydrogen bonding while the other does not
C) one involves salts and water while the other doesn't involve water
D) one involves ionic molecules interacting with other ionic molecules while the other deals with
polar molecules
E) none of the above
Answer: A
9) Which of the following describes an aqueous solution?
A) a mixture of some compound dissolved in water
B) a mixture of polar molecules dissolved in a nonpolar solvent
C) a mixture of water dispersed in an ionic compound
D) a mixture of nonpolar molecules dissolved in a polar solvent
E) none of the above
Answer: A
10) What is a hydrogen bond?
A) a special type of dipole-dipole attraction involving hydrogen bound to a highly
electronegative atom
B) a special type of dipole-dipole attraction involving hydrogen bound to any other atom
C) a special type of dipole-dipole attraction involving hydrogen bound to another hydrogen atom
D) a special type of attraction involving any molecules that contain hydrogens
E) none of the above
Answer: A
11) Which of the following molecules is most likely to show the strongest hydrogen bonding?
A) CH3OH
B) CH3SH
C) CH4
D) H-C C-H
E) A, B and C
Answer: A
12) Which of the following molecules is most likely to show a dipole-dipole interaction?
A) CH3OH
B) CH3SH
C) CH4
D) H-C C-H
E) A and B
Answer: E
13) Which of the following molecules is most likely to show a dipole-dipole interaction?
A) H2S
B) CO2
C) CH4
D) H-C C-H
E) none of the above
Answer: A
14) Which of the following is the main form of intermolecular attractions among water
molecules?
A) hydrogen bonding
B) induced dipole-induced dipole
C) covalent bonding
D) ion-dipole
E) polar-induced polar
Answer: A
15) Given the above diagram, describe what happens electronically between these two
molecules.
A) Oxygen B becomes slightly positively charged due to the electrons on the water molecule.
B) Oxygen A becomes slightly positively charged due to the electrons on the water molecule.
C) Oxygen W becomes slightly negatively charged due to the oxygen molecule.
D) Oxygen W becomes slightly positively charged due to the oxygen molecule.
E) none of the above
Answer: A
16) Given the following diagram, describe what happens electronically between these two
molecules.
A) Oxygen A becomes slightly positively charged due to the protons on the water molecule.
B) Oxygen B becomes slightly positively charged due to the protons on the water molecule.
C) Oxygen A becomes slightly negatively charged due to the oxygen molecule.
D) Hydrogens on oxygen W becomes slightly positively charged due to the oxygen molecule.
E) none of the above
Answer: A
17) In which of the following molecules will water induce a temporary dipole?
A) CO2
B) O2
C) N2
D) all of the above
E) none of the above
Answer: D
18) What is the main difference between a dipole-dipole interaction and a dipole-induced dipole
interaction?
A) Both are similar, but one involves a temporary dipole created by a permanent dipole.
B) Dipole-dipole interactions are weaker because the dipoles are permanent.
C) Dipole-induced dipole interactions are stronger because the induced dipoles can be formed at
any time.
D) Both are identical.
E) none of the above
Answer: A
19) Which of the following is most likely to have the weakest induced dipole-induced dipole
interaction?
A) Cl2
B) Br2
C) F2
D) I2
E) All of the above have the same interactions.
Answer: C
20) Which of the following would have the highest boiling point?
A) Cl2
B) Br2
C) F2
D) I2
E) not enough information given
Answer: D
21) Which of the following would have the lowest melting point?
A) CCl4
B) CBr4
C) CF4
D) CI4
E) not enough information given
Answer: C
22) Which of the following would have the highest boiling point?
A) C6H14
B) C8H18
C) C10H22
D) C12H26
E) not enough information given
Answer: D
23) Which of the following would have the smallest number of induced dipole-induced dipole
interactions?
A) C6H14
B) C8H18
C) C10H22
D) C12H26
E) not enough information given
Answer: A
24) Which of the following intermolecular forces best describes why nonpolar molecules like
gasoline (C8H18) have only limited solubility in water?
A) dipole-dipole
B) induced dipole-induced dipole
C) dipole-induced dipole
D) ion-dipole
E) Both A and B
Answer: E
25) Which of the following intermolecular forces best describes why molecules like sucrose
(which has many OH groups) are very water soluble?
A) dipole-dipole
B) induced dipole-induced dipole
C) dipole-induced dipole
D) ion-dipole
E) hydrogen bonding
Answer: E
26) Which of the following intermolecular forces best describes why molecules like CF 3CF3 are
soluble in liquid CO2?
A) dipole-dipole
B) induced dipole-induced dipole
C) dipole-induced dipole
D) ion-dipole
E) hydrogen bonding
Answer: B
27) The charges with sodium chloride are all balanced-for every positive sodium ion there is a
corresponding negative chloride ion. Since its charges are balanced, how can sodium chloride be
attracted to water, and vice versa?
A) Dispersion forces come into play as the sodium chloride and water come into close proximity.
B) Hydrogen bonding in water allows the sodium chloride molecule to be attracted to the water
molecule.
C) As a water molecule gets close to the sodium chloride it can distinguish the various ions and it
is thus attracted to an individual ion by ion-dipole forces.
D) This is not a matter of attraction. Sodium chloride dissolves in water because water provides a
medium in which the individual sodium and chloride ions can disperse.
Answer: C
28) Why is calcium fluoride, CaF2, a high melting point crystalline solid while stannic chloride,
SnCl4, is a volatile liquid?
A) There is no theory to predict the physical property of melting point. Melting point
temperatures are empirically determined.
B) Actually, we would predict these results to be the opposite. Since each metal is combined
with a group 17 halogen, the heavier metal (tin) combination should have the higher melting
point.
C) CaF2 is a small, linear, non-polar molecule, while SnCl4 is a huge tetrahedral structure.
Therefore the bonds in calcium fluoride tend to give it a higher melting point temperature.
D) Ionic compounds formed by elements on opposite sides of the periodic table, like CaF 2, tend
to have higher melting points than more covalently bonded structures, like SnCl 4.
Answer: D
29) Why are ion-dipole attractions stronger than dipole-dipole attractions?
A) The chemical bond in an ion-dipole molecule is similar also a covalent bond.
B) The magnitude of the electric charge associated with an ion is much greater.
C) Dipole areas are subject to changing from positive to negative regions on the molecule.
D) Like charge (dipole) does not attract like charge (another dipole.)
Answer: B
30) Chlorine, Cl2, is a gas at room temperature, but bromine, Br 2, is a liquid. Explain.
A) Chlorine atoms are larger and this makes the formation of induced dipole-induced dipole
attractions more favorable.
B) Bromine atoms are larger and this makes the formation of induced dipole-induced dipole
attractions more favorable.
C) The smaller chlorine molecules are able to pack together in a tighter physical orientation.
D) The bromine ions are held together by ionic bonds.
Answer: B
31) Plastic wrap is made of nonpolar molecules and is able to stick well to polar surfaces, such as
glass, by way of dipole/induced dipole molecular attractions. How is it that plastic wrap also
sticks to itself so well?
A) by way of dipole-dipole molecular attractions
B) by way of dipole-induced dipole molecular attractions
C) Ions are formed as the plastic rubs against itself.
D) by way of induced dipole-induced dipole molecular attractions
Answer: D
32) Dipole-induced dipole forces of attraction exist between water and gasoline, and yet these
two substances do not mix because water has such a strong attraction for itself. Which of the
following compounds might best help to make these two substances mix into a single liquid
phase?
A) the molecule on the far left because the O-H bond is polar and the carbon and hydrogen bonds
are nonpolar
B) the molecule in the middle because when the salts mix into the water, it will help separate the
water and decrease the attraction for itself
C) The molecule on the right will form attractions with the polar ends of the water, allowing the
gasoline a chance to mix with the water.
D) All of these molecules would be equally effective at increasing the mixing of gasoline and
water.
Answer: A
33) How are oxygen molecules attracted to water molecules?
A) The attraction between oxygen and water molecules is a classic example of dipole-dipole
interaction.
B) The hydrogen bonding in water causes the attraction of the oxygen atoms in the O2 molecule
to water.
C) As a water molecule is brought close to an oxygen molecule an induced dipole results in the
O2 molecule causing the attraction.
D) The attraction of oxygen and water molecules for one another is part of the common atom
effect. Since both molecules contain oxygen, there is a built-in attraction.
Answer: C
34) List the following compounds in order of increasing boiling point: Cl 4, CBr4, CCl4, CF4.
A) Cl4, CBr4, CCl4, CF4
B) CF4, CBr4, CCl4, Cl4
C) Cl4, CCl4, CBr4, CF4
D) CF4, Cl4, CBr4, Cl4
Answer: D
35) Why is the surface area of a gecko's foot so extensive?
A) A gecko, like all amphibians, needs extensive surface area under foot for stability on land as
well as mobility in water.
B) A gecko's foot acts like a large dipole and thus allows for ion-dipole interaction in water.
C) The greater the surface area the greater the number of induced dipole-induced dipole forces of
attraction that can occur between the gecko's foot and the surface.
D) The extensive surface area, once charged by the gecko's body, allows for the dipole-dipole
attraction of every contact surface.
Answer: C
36) Consider the boiling points of the following compounds and their solubilities in roomtemperature water. Why does the solubilities in water go down as the boiling points of these
alcohols go up.
A) Larger molecules are less attracted to one another by induced dipole-induced dipole as well as
by dipole-dipole and dipole-induced dipole attractions.
B) As the boiling increases, it is more difficult to keep the alcohol from evaporating out of
solution.
C) As the boiling point increases, the size of the alcohol molecules decreases.
D) Larger molecules are more attracted to one another by induced dipole-induced dipole as well
as by dipole-dipole and dipole-induced dipole attractions.
Answer: D
37) The boiling point of 1,4-butanediol is 230°C. Would you expect this compound to be soluble
or insoluble in room-temperature water?
A) Since there are no polar areas on this molecule, it is insoluble in water at room temperature.
B) A high boiling point means that the substance interacts with itself quite strongly. Therefore
this molecule is not soluble in water.
C) Since there are polar areas on this molecule, it is insoluble in water at room temperature.
D) Water would be attracted to both ends of 1,4 butanediol, and it is infinitely soluble in water.
Answer: D
38) Two chemical structures are shown, one of a typical gasoline molecule and the other of a
typical motor oil molecule. Which is which?
Base your reasoning not on memorization but rather upon what you know about molecular
interactions and the various physical properties of gasoline and motor oil.
A) Structure A represents the gas molecule because there are more bonds to gain energy from,
giving it a higher energy content than oil.
B) Structure A represents motor oil, illustrating a molecule with greater induced dipole-induced
dipole molecular interactions thus, the molecules are strongly attracted to one another.
C) Structure B represents the oil molecule. Because oil molecules are smaller, they can compact
closer together, giving the appearance of a thicker solution than gasoline.
D) Structure B represents crude oil which is processed to generate longer molecules of gasoline
to prevent toxic vapors from harming consumers.
Answer: B
39) Why are the melting temperatures of most ionic compounds far greater than the melting
temperatures of most covalent compounds?
A) Ionic bonds are so much stronger than the molecular attractions between covalently bonded
compounds.
B) Covalent bonds are not as strong as ionic bonds.
C) As a solid, salts have a very organized crystalline structure which takes a lot of energy to
break apart.
D) Most covalent compounds have at least one weak bond in their structure that is easily broken
when heat is added.
Answer: A
Test Bank for Conceptual Physical Science
Paul Hewitt, John Suchocki, Leslie Hewitt
9780321752932, 9780134060491
