Chemistry for Changing Times

John W. Hill; Terry W. McCreary; Doris K. Kolb

Chapter 4 Chemical Bonds - all with Video Answers

Educators

Chapter Questions

01:28

Problem 1

How does sodium metal differ from sodium ions (in sodium chloride, for example) in properties?

Sima Sarker

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01:22

Problem 2

Why is potassium metal so much more reactive than potassium ion (KOH, for example)?

Lottie Adams

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02:08

Problem 3

What are the structural differences among chlorine atoms, chlorine molecules, and chloride ions? How do their properties differ?

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01:09

Problem 4

How many electrons are in a duet, and how many electrons are in an octet?

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02:15

Problem 5

What are the charges on simple ions formed from atoms of the following?
a. group 3 A elements
b. group 7 A elements
c. group 5A elements
d. group 2 A elements

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01:10

Problem 6

How many electrons are needed for the elements below to complete their octet?
a. group 1A elements
b. group 6 A elements
c. group 5A elements
d. group 2 A elements

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02:32

Problem 7

In what group of the periodic table would elements that form ions with the following charges likely be found?
a. $4-$
b. 3-
c. $1-$
d. $2+$

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01:41

Problem 8

How many covalent bonds do each of the following usually form? You may refer to the periodic table.
a. B
b. Br
c. S
d. F
e. I
f. P

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02:15

Problem 9

Of the elements $\mathrm{H}, \mathrm{O}, \mathrm{N},$ and $\mathrm{C},$ which one $(\mathrm{s})$ can readily form triple bonds?

Rabia Bibi

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01:41

Problem 10

Write Lewis symbols for each of the following elements. You may use the periodic table.
a. calcium
b. sulfur
c. silicon

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01:38

Problem 11

Write Lewis symbols for each of the following elements. You may use the periodic table.
a. lithium
b. carbon
c. nitrogen

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02:31

Problem 12

Write the Lewis symbol for each species in the following pairs.
a. $\mathrm{Na}, \mathrm{Na}^{+}$
b. $\mathrm{Ca}, \mathrm{Ca}^{2+}$
c. $\mathrm{Cl}, \mathrm{Cl}^{-}$

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04:30

Problem 13

Write Lewis formulas for each of the following.
a. sodium iodide
b. potassium sulfide
c. calcium chloride
d. aluminum fluoride

Rabia Bibi

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01:15

Problem 14

Write Lewis formulas for each of the following.
a. lithium bromide
b. strontium sulfide
c. sodium nitride
d. aluminum oxide

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02:54

Which of the following statements regarding Lewis dot symbols of ions is false?
a. In magnesium oxide, $\mathrm{O}^{2-}$ has eight electrons.
b. $\mathrm{Mg}^{2+}$ always has one electron around it.
c. In sodium chloride, $\mathrm{Na}^{+}$ has no electrons around it.
d. In ionic compounds containing chloride, ions, $\mathrm{Cl}^{-}$ is isoelectronic with Ar.

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01:20

Problem 16

Pair (match) the names and symbols for the ions below:
a. nitride ion
b. $\mathrm{Fe}^{2+}$
c. cuprous ion
d. $\mathrm{N}^{3-}$
e. ferrous ion
f. $\mathrm{Cu}^{+}$
g. silver ion
h. $\mathrm{Ag}^{+}$

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01:08

Problem 17

Without referring to Table $4.2,$ supply a symbol given the name or a name given the symbol for each of the following ions:
a. magnesium ion
b. $\mathrm{Li}^{+}$
c. $\mathrm{Cl}^{-}$
d. oxide ion
e. $\mathrm{Cu}^{+}$
f. silver ion

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01:06

Problem 18

Refer to the beginning paragraphs of Section $4.5,$ and use that information to name the following ions:
a. $\mathrm{Mn}^{2+}$
b. $\mathrm{Hg}^{2+}$
c. $\mathrm{Mn}^{7+}$

Sima Sarker

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01:06

Problem 19

Refer to the beginning paragraphs of Section $4.5,$ then use that information to name the following ions.
a. $\mathrm{Mo}^{4+}$
b. $\mathrm{Mo}^{6+}$

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01:07

Problem 20

Refer to the beginning paragraphs of Section $4.5,$ and write symbols for:
a. chromium(III) ion
b. vanadium(II) ion
c. titanium(IV) ion

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01:09

Problem 21

Refer to the beginning paragraphs of Section $4.5,$ then write symbols for:
a. manganese(II) ion
b. manganese(III) ion
c. manganese(VII) ion

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01:33

Problem 22

For copper and iron ions, we sometimes use the $-i c$ and -ous endings. Which ending indicates the more positively charged ion?

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01:21

Problem 23

Write a formula to match the name or a name to match the formula of the following binary ionic compounds:
a. sodium iodide
b. $K C l$
c. copper(I) oxide
d. $\mathrm{MgF}_{2}$
e. iron(II) bromide
f. $\mathrm{FeBr}_{3}$

Sima Sarker

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01:20

Problem 24

Write a formula to match the name or a name to match the formula of the following binary ionic compounds:
a. $\mathrm{KCl}$
b. iron(II) bromide
c. $\mathrm{Li}_{2} \mathrm{O}$
d. sodium iodide
e. $\mathrm{FeI}_{3}$
f. copper(I) oxide

Sima Sarker

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01:16

Problem 25

There are two common binary ionic compounds formed from chromium and oxygen. One of them contains chromium(III) ions; the other contains chromium(VI) ions. Write the formulas for the two compounds, and name them.

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01:18

Problem 26

One of two binary ionic compounds is often added to toothpaste. One of these compounds contains sodium and fluorine; the other contains tin(II) ions and fluorine. Write the formulas for these two compounds, and name them.

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01:34

Problem 27

Pair (match) the names and formulas for the following polyatomic ionic compounds:
a. ammonium nitrate
b. $\mathrm{FePO}_{4}$
c. calcium carbonate
d. $\mathrm{NH}_{4} \mathrm{NO}_{3}$
e. iron(III) phosphate
f. $\mathrm{Ca}\left(\mathrm{CH}_{3} \mathrm{CO}_{2}\right)_{2}$
g. calcium acetate
h. $\mathrm{CaCO}_{3}$

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01:30

Problem 28

Supply a formula to match the name or a name to match the formula for the following:
a. potassium hydroxide
b. $\mathrm{CsMnO}_{4}$
c. barium nitratee
d. cobalt(II) nitrate
e. $\mathrm{Zn}\left(\mathrm{NO}_{3}\right) \mathrm{O}_{2}$
f. $\mathrm{FeSO}_{4}$

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01:23

Problem 29

Supply a formula to match the name or a name to match the formula for the following:
a. $\mathrm{AgNO}_{2}$
b. sodium chromate
c. $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{~S}$
d. magnesium carbonate
e. copper(II) chloride
f. $\mathrm{KMnO}_{4}$

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02:54

Problem 30

How is a covalent bond different from an ionic bond?

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01:21

Problem 31

Use Lewis dot symbols to show the sharing of electrons between a hydrogen atom and a fluorine atom.

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01:18

Problem 32

Use Lewis dot symbols to show the sharing of electrons between two bromine atoms to form a bromine $\left(\mathrm{Br}_{2}\right)$ molecule. Label all electron pairs as bonding pairs (BPs) or lone pairs (LPs).

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02:21

Problem 33

Use Lewis dot symbols to show the sharing of electrons between a phosphorus atom and hydrogen atoms to form a molecule in which phosphorus has an octet of electrons.

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02:08

Problem 34

Use Lewis dot symbols to show the sharing of electrons between a silicon atom and hydrogen atoms to form a molecule in which silicon has an octet of electrons.

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03:00

Problem 35

Use Lewis dot symbols to show the sharing of electrons between a carbon atom and chlorine atoms to form a molecule in which each atom has an octet of electrons.

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02:56

Problem 36

Use Lewis dot symbols to show the sharing of electrons between a nitrogen atom and fluorine atoms to form a molecule in which each atom has an octet of electrons.

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01:56

Problem 37

When a hydrogen atom covalently bonds to another atom, how many electrons associated with this hydrogen atom become involved in such a bond? (Explain your answer.)

Rabia Bibi

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01:45

Problem 38

Pair (match) the names and formulas for the following bi nary covalent compounds:
a. dichlorine monoxide
b. $\mathrm{ClO}$
c. chlorine monoxide
d. $\mathrm{Cl}_{2} \mathrm{O}_{7}$
e. dichlorine trioxide
f. $\mathrm{Cl}_{2} \mathrm{O}$
g. dichlorine heptoxide
h. $\mathrm{Cl}_{2} \mathrm{O}_{3}$

Sima Sarker

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01:28

Problem 39

Supply a formula for the name or a name for the formul? for the following covalent compounds:
a. dinitrogen tetroxide
b. bromine trichloride
c. $\mathrm{OF}_{2}$
d. nitrogen triiodide
e. $\mathrm{CBr}_{4}$
f. $\mathrm{N}_{2} \mathrm{~S}_{4}$

Sima Sarker

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01:38

Problem 40

Supply a formula for the name or a name for the formula for the following covalent compounds:
a. sulfur trioxide
b. chlorine trifluoride
c. $\mathrm{PF}_{5}$
d. $\mathrm{CI}_{4}$
e. dinitrogen trioxide
f. $\mathrm{P}_{4} \mathrm{O}_{6}$

Sima Sarker

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04:40

Problem 41

Write Lewis formulas that follow the octet rule for the following covalent molecules:
a. $\mathrm{SiH}_{4}$
b. $\mathrm{N}_{2} \mathrm{~F}_{4}$
c. $\mathrm{CH}_{5} \mathrm{~N}$
d. $\mathrm{H}_{2} \mathrm{CO}$
e. $\mathrm{NOH}_{3}$
f. $\mathrm{H}_{3} \mathrm{PO}_{3}$

Rabia Bibi

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01:41

Problem 42

Write Lewis formulas that follow the octet rule for the fol-
lowing covalent molecules:
a. $\mathrm{NH}_{2} \mathrm{Cl}$
b. $C_{2} H_{4}$
c. $\mathrm{H}_{2} \mathrm{SO}_{4}$
d. $\mathrm{C}_{2} \mathrm{~N}_{2}$
e. $\mathrm{COCl}_{2}$
f. $\mathrm{SCl}_{2}$

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05:05

Problem 43

Write Lewis formulas that follow the octet rule for the following ions:
a. $\mathrm{ClO}^{-}$
b. $\mathrm{HPO}_{4}^{2-}$
c. $\mathrm{BrO}_{3}^{-}$

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02:41

Problem 44

Write Lewis formulas that follow the octet rule for the following ions:
a. $\mathrm{CN}^{-}$
b. $\mathrm{ClO}_{2}$
c. $\mathrm{HSO}_{4}^{2-}$

Rabia Bibi

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01:35

Problem 45

If element A bonds covalently with element $\mathrm{B}$, then what must the electronegativity difference between $\mathrm{A}$ and $\mathrm{B}$ be for this bond to be polar?

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01:29

Problem 46

If element $X$ bonds covalently with element $Y$, then what must the electronegativity difference between $X$ and $Y$ be for this bond to be nonpolar?

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03:07

Problem 47

Classify the following covalent bonds as polar or nonpolar.
a. $\mathrm{H}-\mathrm{O}$
b. $\mathrm{N}-\mathrm{F}$
c. $C l-B$

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01:14

Problem 48

Classify the following covalent bonds as polar or nonpolar.
a. $\mathrm{H}-\mathrm{N}$
b. $\mathrm{O}-\mathrm{Be}$
c. $\mathrm{P}-\mathrm{F}$

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01:56

Problem 49

Use the symbol $\mapsto$ to indicate the direction of the dipole in each polar bond in Problem 47 .

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01:13

Problem 50

Use the symbol $\mapsto$ to indicate the direction of the dipole in each polar bond in Problem 48

Lottie Adams

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01:49

Problem 51

Use the symbols $\delta+$ and $\delta-$ to indicate partial charges, if any, on the following bonds.
a. $\mathrm{Si}-\mathrm{O}$
b. $\mathrm{F}-\mathrm{F}$
c. $F-N$

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01:52

Problem 52

Use the symbols $\delta+$ and $\delta-$ to indicate partial charges, if any, on the following bonds.
a. $\mathrm{N}-\mathrm{H}$
b. $C-F$
c. $S=S$

Sima Sarker

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02:02

Problem 53

Classify the bonds in the following as ionic or covalent. For bonds that are covalent, indicate whether they are polar or nonpolar.
a. $\mathrm{Na}_{2} \mathrm{O}$
b. ICl
c. $\mathrm{CaF}_{2}$
d. $\mathrm{Br}_{2}$

Sima Sarker

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02:52

Problem 54

Classify the bonds in the following as ionic or covalent. For bonds that are covalent, indicate whether they are polar or nonpolar.
a. $\mathrm{MgO}$
b. $\operatorname{SrCl}_{2}$
c. $\mathrm{NH}_{3}$
d. $\mathrm{H}_{2} \mathrm{~S}$

Sima Sarker

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02:33

Problem 55

Rank the following bonds in terms of increasing polarity.
a. $\mathrm{H}-\mathrm{F}$
b. $\mathrm{H}-\mathrm{Cl}$
c. $C-C l$
d. $C-$ Br

Sima Sarker

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01:27

Problem 56

Pair (match) the VSEPR predicted shape to the listed molecules:
a. $\mathrm{AlCl}_{3}$
b. linear
c. $\mathrm{CSe}_{2}$
d. trigonal planar
e. $\mathrm{SeH}_{2}$
f. bent
g. $\mathrm{SiI}_{4}$
h. tetrahedral

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01:30

Problem 57

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01:53

Problem 58

Use VSEPR theory to predict the shape of each of the following molecules
a. chloroform $\left(\mathrm{CHCl}_{3}\right)$
b. boron trichloride $\left(\mathrm{BCl}_{3}\right)$
c. carbon tetrafluoride $\left(\mathrm{CF}_{4}\right)$
d. sulfur difluoride $\left(\mathrm{SF}_{2}\right)$
e. nitrogen triiodide $\left(\mathrm{NI}_{3}\right)$
f. dichlorodifluoromethane $\left(\mathrm{CCl}_{2} \mathrm{~F}_{2}\right)$

Lottie Adams

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01:09

Problem 59

Despite the large electronegativity difference between fluorine and beryllium atoms, $\mathrm{BeF}_{2}$ forms linear molecules in gas phase. Are these molecules polar or nonpolar? Explain.

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01:20

Problem 60

The molecule $\mathrm{SF}_{2}$ is bent. Is it polar or nonpolar? Explain.

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01:20

Problem 61

Is $\mathrm{BCl}_{2} \mathrm{~F}$ polar or nonpolar? Explain.

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01:51

Problem 62

Look again at the molecules in Problem $57 .$ For each one, are the bonds polar? What are the approximate bond angles? Is the molecule as a whole polar?

Lottie Adams

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01:34

Problem 63

Look again at the molecules in Problem $58 .$ For each one, are the bonds polar? What are the approximate bond angles? Is the molecule as a whole polar?

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01:04

Problem 64

What makes the molecule of $\mathrm{SO}_{2}$ polar?

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01:01

Problem 65

What makes the molecule of $\mathrm{SO}_{3}$ nonpolar?

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01:06

Problem 66

Is it possible for a molecule of $\mathrm{CH}_{2} \mathrm{Cl}_{2}$ to be nonpolar $(\mathrm{C}$ is the central atom)? Explain.

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01:49

Problem 67

Is $\mathrm{H}_{2} \mathrm{O}$ more or less polar than $\mathrm{SCl}_{2} ?$

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02:25

Problem 68

Which of the following species (atoms or molecules) are free radicals?
a. Br
b. $\mathrm{CH}_{3}$
c. I

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02:32

Problem 69

Which of the following species (atoms or molecules) are free radicals?
a. $P$
b. CN
c. $\mathrm{SO}_{2}$

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03:34

Problem 70

Free radicals are one class of molecules in which atoms do not conform to the octet rule. Another exception involves atoms with fewer than eight electrons, as seen in elements of group 3 and in beryllium. In some covalent molecules, these atoms can have six or four electrons, respectively. Write Lewis structures for the following covalent molecules:
a. $\mathrm{AlBr}_{3}$
b. $\mathrm{BeH}_{2}$
c. $\mathrm{BH}_{3}$

Sima Sarker

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04:51

Problem 71

Exceptions to the octet rule include molecules that have atoms with more than 8 valence electrons, most typically 10 or 12 . Atoms heavier than Si can expand their valence shell, meaning that they can accommodate the "extra" electrons in unoccupied, higher-energy orbitals. Draw Lewis structures for the following molecules or ions:
a. $\mathrm{XeF}_{4}$
b. $I_{3}^{-}$
c. $\mathrm{SF}_{4}$
d. $\mathrm{KrF}_{2}$

Rabia Bibi

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01:41

Problem 72

Why does neon tend not to form chemical bonds?

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01:14

Problem 73

Draw an electrostatic potential diagram of the $\mathrm{H}_{2} \mathrm{~S}$ molecule. Use the symbols $\delta+$ and $\delta-$ to indicate the polarity of the molecule.

Lottie Adams

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01:40

Problem 74

The gas phosphine $\left(\mathrm{PH}_{3}\right)$ is used as a fumigant to protect stored grain and other durable produce from pests. Phosphine is generated where it is to be used by adding water to aluminum phosphide or magnesium phosphide. Give formulas for these two phosphides.

Sima Sarker

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03:36

Problem 75

Explain why the angle between $\mathrm{Cl}-\mathrm{S}-\mathrm{Cl}$ is less than $109.5^{\circ}$ in $\mathrm{SCl}_{2}$

Sima Sarker

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01:03

Problem 76

There are two different covalent molecules with the formula $\mathrm{C}_{2} \mathrm{H}_{6} \mathrm{O}$. Write Lewis formulas for the two molecules.

Lottie Adams

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02:09

Problem 77

Solutions of iodine chloride (ICl) are used as disinfectants. Is the compound ICl ionic, polar covalent, or nonpolar covalent?

Rabia Bibi

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05:09

Problem 78

Consider the hypothetical elements $X, Y,$ and $Z,$ which have the following Lewis symbols:
$$
\begin{array}{lll}
\ddot{\mathrm{X}} \cdot & : \ddot{\mathrm{Y}} \cdot & : \dot{\mathrm{Z}} \cdot
\end{array}
$$
a. To which group in the periodic table would each element belong?
b. Write the Lewis formula for the simplest compound each would form with hydrogen.
c. Write Lewis formulas for the ions that would be formed when X reacted with sodium and when $Y$ reacted with sodium.

Rabia Bibi

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02:07

Problem 79

Potassium is a soft, silvery metal that reacts violently with water and ignites spontaneously in air. Your doctor recommends that you take a potassium supplement. Would you take potassium metal? If not, what would you take?

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01:15

Problem 80

What is wrong with the phrase "just a few molecules of potassium iodide"?

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09:24

Problem 81

Use subshell notation to write an electron configuration for the most stable simple ion formed by each of the following elements.
a. $\mathrm{Ca}$
b. $R b$
c. S
d. I
e. $N$
f. Se

Rabia Bibi

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03:25

Problem 82

Why is $\mathrm{Na}^{+}$ smaller than Na? Why is $\mathrm{Cl}^{-}$ larger than Cl?

Rabia Bibi

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01:43

Problem 83

The halogens $(\mathrm{F}, \mathrm{Cl}, \mathrm{Br},$ and $\mathrm{I})$ tend to form only one single bond in binary molecules. Explain.

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01:05

Problem 84

A science magazine for the general public contains this statement: "Some of these hydrocarbons are very light, like methane gas-just a single carbon molecule attached to three hydrogen molecules." Evaluate the statement, and correct any inaccuracies.

Lottie Adams

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01:17

Problem 85

Sodium tungstate is $\mathrm{Na}_{2} \mathrm{WO}_{4}$. What is the formula for cobalt (III) tungstate?

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00:39

Problem 86

Scientists estimate that the atmosphere of Titan (a moon of Saturn) consists of about $98.4 \%$ nitrogen and $1.6 \%$ methane. They have also found traces of organic molecules with the molecular formulas $\mathrm{C}_{2} \mathrm{H}_{4}, \mathrm{C}_{3} \mathrm{H}_{4}, \mathrm{C}_{4} \mathrm{H}_{2}, \mathrm{HCN}, \mathrm{HC}_{3} \mathrm{~N},$ and $\mathrm{C}_{2} \mathrm{~N}_{2} .$ Write possible Lewis formulas for each of these molecules.

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01:19