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Chapter 4 Compounds and Their Bonds. 4.1 Valence Electrons 4.2 Octet Rule and Ions. Valence Electrons. The valence electrons are the electrons in the outer shell. - PowerPoint PPT Presentation
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4.1 4.1 Valence Electrons Valence Electrons
4.2 4.2 Octet Rule and Ions Octet Rule and Ions
Chapter 4 Chapter 4 Compounds and Their BondsCompounds and Their Bonds
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The The valence electronsvalence electrons are the are the electrons in the outer shell. electrons in the outer shell.
The electrons in the outer shell The electrons in the outer shell have the most contact with other have the most contact with other atoms and strongly influence the atoms and strongly influence the chemical properties of atoms. chemical properties of atoms.
Valence ElectronsValence Electrons
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Number of Valence ElectronsNumber of Valence Electrons
For Group A elements, the number of For Group A elements, the number of valence electrons is the number of valence electrons is the number of electrons in the electrons in the ss and and pp subshells of the subshells of the outer shell.outer shell.
In the electron configuration for In the electron configuration for phosphorus, there are 5 valence phosphorus, there are 5 valence electrons in the electrons in the s s and and pp subshells with subshells with the highest number. the highest number.
5 valence electrons5 valence electrons
P P Group 5AGroup 5A 1 1ss2222ss2222pp6633ss2233pp33
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Valence Electrons for GroupsValence Electrons for Groups
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State the number of valence electrons State the number of valence electrons for each. for each.
A. MagnesiumA. Magnesium
1) 21) 2 2) 62) 6 3) 83) 8
B. OxygenB. Oxygen
1) 21) 2 2) 42) 4 3) 63) 6
C. PotassiumC. Potassium
1) 11) 1 2) 22) 2 3) 73) 7
Learning CheckLearning Check
6
State the number of valence electrons for State the number of valence electrons for each. each.
A. MagnesiumA. Magnesium
1) 2 1) 2 Group 2AGroup 2A 1 1ss2222ss2222pp6633ss2 2
B. OxygenB. Oxygen
3) 63) 6 Group 6AGroup 6A 1 1ss2222ss2 2 22pp4 4
C. PotassiumC. Potassium
1) 11) 1 Group 1AGroup 1A 1 1ss2222ss2222pp6633ss2233pp6644ss11
SolutionSolution
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Electron Dot StructureElectron Dot Structure
An electron-dot An electron-dot structure is a structure is a convenient way to convenient way to represent the valence represent the valence electrons.electrons.
For example, the two For example, the two valence electrons for valence electrons for magnesium are placed magnesium are placed as single dots on any as single dots on any two sides of the Mg two sides of the Mg symbol.symbol.
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Electron-Dot StructuresElectron-Dot Structures
Dot structures are used for Group A Dot structures are used for Group A elements.elements.
The valence electrons are placed on the sides The valence electrons are placed on the sides of the symbol of an element.of the symbol of an element.
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A. X is the electron dot formula forA. X is the electron dot formula for
1) Na1) Na 2) K2) K 3) Al3) Al
B. B. X X is the electron dot formula is the electron dot formula
ofof
1) B1) B 2) N2) N 3) P 3) P
Learning CheckLearning Check
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A. X is the electron dot formula forA. X is the electron dot formula for
1) Na1) Na 2) K2) K
B.B. XX iiss the electron dot formula the electron dot formula
ofof
2) N2) N 3) P 3) P
SolutionSolution
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The stability of the noble gases is associated The stability of the noble gases is associated with with 8 valence electrons8 valence electrons (He has 2).(He has 2).
Ne Ne 2,2, 88ArAr 2, 8,2, 8, 88KrKr 2, 8, 18, 2, 8, 18, 88
Atoms can become more stable by acquiring Atoms can become more stable by acquiring an octet (8 electrons) in the outer shell. an octet (8 electrons) in the outer shell.
The process of acquiring an octet involves The process of acquiring an octet involves the the loss, gain, or sharingloss, gain, or sharing of valence of valence electrons.electrons.
Octet RuleOctet Rule
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Ionization EnergyIonization Energy
Ionization Ionization energyenergy is the is the energy it takes energy it takes to remove a to remove a valence valence electron.electron.
Metals have Metals have lower ionization lower ionization energies and energies and nonmetals have nonmetals have higher higher ionization ionization energies. energies.
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Metals acquire octets by Metals acquire octets by losinglosing valencevalence electrons.electrons.
The loss of electrons converts an atom to The loss of electrons converts an atom to an an ionion that has the electron configuration that has the electron configuration of the nearest noble gas.of the nearest noble gas.
Metals form Metals form positivepositive ionsions because they because they have fewer electrons than protons.have fewer electrons than protons.
Group 1A metals Group 1A metals ion ion 1+1+
Group 2A metals Group 2A metals ion ion 2+2+
Group 3A metals Group 3A metals ion ion 3+3+
Metals Form Positive IonsMetals Form Positive Ions
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Give the ionic charge for each ion. Give the ionic charge for each ion.
A. 12 pA. 12 p+ + and 10 e and 10 e--
1) 01) 0 2) 2+2) 2+ 3) 2-3) 2-
B. 50pB. 50p++ and 46 e and 46 e--
1) 2+1) 2+ 2) 4+2) 4+ 3) 4-3) 4-
C. 15 pC. 15 p++ and 18e and 18e--
2) 3+ 2) 3+ 2) 3-2) 3- 3) 3) 5- 5-
Learning CheckLearning Check
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Give the ionic charge for each ion.Give the ionic charge for each ion.
A. 12 pA. 12 p+ + and 10 e and 10 e--
2) 2+2) 2+
B. 50pB. 50p++ and 46 e and 46 e--
2) 4+2) 4+
C. 15 pC. 15 p++ and 18e and 18e--
2) 3-2) 3-
SolutionSolution
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Sodium forms an octet by losing its one Sodium forms an octet by losing its one valence electron.valence electron.Na Na – e – e Na Na ++
1s1s222s2s222p2p663s3s11 1s1s222s2s222p2p66 (= Ne)(= Ne)
A positive ion forms with a +1 charge.A positive ion forms with a +1 charge.Sodium atomSodium atom Sodium ionSodium ion 11 p11 p++ 11 p 11 p++
11 e11 e-- 10 e10 e--
00 1 1 ++
Formation of a Sodium Ion, Formation of a Sodium Ion, NaNa++
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Magnesium forms an octet by losing its Magnesium forms an octet by losing its two valence electrons.two valence electrons. Magnesium atomMagnesium atom Magnesium ionMagnesium ion
Mg Mg – 2e – 2e MgMg2+2+
1s1s222s2s222p2p663s3s22 1s1s222s2s222p2p66 (= (= Ne)Ne)
A positive ion forms with a +2 charge.A positive ion forms with a +2 charge. 12 p12 p++ 12 p12 p++
12 e12 e- - 10 e10 e--
00 2 2 ++
Formation of MgFormation of Mg2+2+
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When nonmetals When nonmetals gain electronsgain electrons to to achieve an octet arrangement, they achieve an octet arrangement, they form form negative ionsnegative ions. .
The ionic charge of a nonmetal is The ionic charge of a nonmetal is 3-, 2-, or 1-.3-, 2-, or 1-.
Formation of Negative IonsFormation of Negative Ions
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Fluorine forms an octet by adding an Fluorine forms an octet by adding an electron to its seven valence electrons.electron to its seven valence electrons.
11--
:: F F + e + e :: F F ::
1s1s222s2s222p2p55 1s1s222s2s222p2p66 (= Ne)(= Ne) A negative ion forms with a -1 charge.A negative ion forms with a -1 charge.
Fluorine atom Fluoride ionFluorine atom Fluoride ion 9 p9 p++ 9 p 9 p++
9 e9 e-- 10 e10 e--
00 1 1 ––
Formation of a Fluoride Ion, FFormation of a Fluoride Ion, F--
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Group Number and IonsGroup Number and Ions
The The Group numberGroup number can be used to can be used to determine the charge of an ion.determine the charge of an ion.
The charge of a positive ion is The charge of a positive ion is equal to its Group number.equal to its Group number.
Group 3A = 3+Group 3A = 3+ The charge of a negative ion is The charge of a negative ion is
obtained by subtracting its Group obtained by subtracting its Group number from 8. number from 8.
Group 6A = - (8-6) = 2-Group 6A = - (8-6) = 2-
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Examples of Ionic ChargesExamples of Ionic Charges
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Some Important Ions in the Some Important Ions in the BodyBody
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A.A. How many valence electrons does How many valence electrons does aluminum have?aluminum have?1) 2e1) 2e-- 2) 3e 2) 3e-- 3) 5e3) 5e--
B.B. How does aluminum acquire an octet? How does aluminum acquire an octet? 1) loses 3e1) loses 3e- - 2) gains 3e2) gains 3e- - 3) gains 3) gains
5e5e--
C. What is the ionic charge of an C. What is the ionic charge of an aluminum ion?aluminum ion?1) 3-1) 3- 2) 5- 2) 5- 3) 33) 3++
D. The symbol for the aluminum ion isD. The symbol for the aluminum ion is1) Al1) Al3+3+ 2) Al 2) Al3-3- 3) Al3) Al++
Learning CheckLearning Check
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A.A. How many valence electrons does How many valence electrons does aluminumaluminumhave?have?2) 3e2) 3e--
B.B. How does aluminum acquire an octet? How does aluminum acquire an octet? 1) loses 3e1) loses 3e- -
C. What is the ionic charge of an aluminum C. What is the ionic charge of an aluminum ion?ion?
3) 33) 3++ D. The symbol for the aluminum ion isD. The symbol for the aluminum ion is
1) Al1) Al3+3+
SolutionSolution
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Chapter 4 Chapter 4 Compounds and Their BondsCompounds and Their Bonds
4.3 4.3 Ionic CompoundsIonic Compounds4.4 4.4 Naming and Writing Naming and Writing
Ionic FormulasIonic Formulas
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Ionic compounds consist of positive and Ionic compounds consist of positive and negative ions.negative ions.
An ionic bond is an attraction between An ionic bond is an attraction between the positive and negative charges. the positive and negative charges.
In an ionic formula, the total charge of In an ionic formula, the total charge of the positive ions is equal to the total the positive ions is equal to the total charge of the negative ions. charge of the negative ions.
total positive charge = total total positive charge = total negative chargenegative charge
Ionic CompoundsIonic Compounds
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The formulas of ionic compounds are The formulas of ionic compounds are determined from the charges on the ions.determined from the charges on the ions.
atomsatoms ions ions ––
Na Na + + F F :: Na Na+ + :: F F :: NaF NaF
sodium fluorine sodium sodium fluorine sodium fluoridefluoride
The overall charge of NaF is zero (0).The overall charge of NaF is zero (0).
((1+1+ ) + ( ) + (1-1-) = ) = 0 0
Ionic FormulasIonic Formulas
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Charge Balance In NaClCharge Balance In NaCl
The formula does not show the charges of The formula does not show the charges of the ions in the compound.the ions in the compound.
The symbol of the metal is written first, The symbol of the metal is written first, followed by the symbol of the nonmetal.followed by the symbol of the nonmetal.
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Charge Balance In MgClCharge Balance In MgCl22
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Write the formula of the ionic compound Write the formula of the ionic compound that forms from Bathat forms from Ba2+2+ and Cl and Cl..
Write the symbols of the positive ion and Write the symbols of the positive ion and the negative ion. the negative ion. BaBa2+2+ Cl Cl
Balance the charges until the positive Balance the charges until the positive
charge is equal to the negative charge. charge is equal to the negative charge. BaBa2+2+ Cl Cl twotwo ClCl-- neededneeded
ClCl
Write the formula using subscripts for the Write the formula using subscripts for the number of ions for charge balance. number of ions for charge balance. BaClBaCl22
Writing a Formula from Writing a Formula from ChargesCharges
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Write the correct formula for the ionic Write the correct formula for the ionic compound ofcompound of
A. NaA. Na+ + and and SS2-2-
1) NaS1) NaS 2) Na 2) Na22SS 3) NaS3) NaS22
B. AlB. Al3+ 3+ and Cland Cl--
1) AlCl1) AlCl33 2) AlCl 2) AlCl 3) Al3) Al33ClCl
C. MgC. Mg2+2+ and N and N3-3-
1) MgN1) MgN 2) Mg2) Mg22NN33 3) Mg3) Mg33NN22
Learning CheckLearning Check
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A. A. NaNa+ + and and SS2-2-
2) Na2) Na22SS
B. AlB. Al3+ 3+ and Cland Cl--
1) AlCl1) AlCl33
C. MgC. Mg2+ 2+ and Nand N3-3-
3) Mg3) Mg33NN22
SolutionSolution
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Names of IonsNames of Ions
Positive ions are named like the element.Positive ions are named like the element. Negative ions are named by changing the Negative ions are named by changing the
end of the element name to –end of the element name to –ide.ide.
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Complete the names of the following Complete the names of the following ions:ions:
NN33 O O22 F F
_________ _________ __________ __________ _________ _________
PP33 S S22 Cl Cl
_________ __________ __________________ __________ _________
Br Br
__________________
Learning CheckLearning Check
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NN33 OO22 F F
nitridenitride oxideoxide fluoridefluoride
PP33 SS22 Cl Cl
phosphidephosphide sulfidesulfide chloridechloride
Br Br
bromidebromide
SolutionSolution
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The name of a binary ionic The name of a binary ionic compound (two elements) gives the compound (two elements) gives the name of the metal ion first and the name of the metal ion first and the name of the negative ion second.name of the negative ion second.Examples: Examples: NaClNaCl sodium chloridesodium chlorideKK22SS potassium sulfidepotassium sulfideCaICaI22 calcium iodidecalcium iodideAlAl22OO33 aluminum oxidealuminum oxide
Naming Ionic Compounds with Naming Ionic Compounds with Two ElementsTwo Elements
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Write the names of the following Write the names of the following compounds:compounds:
1) Na1) Na33NN ______________________
2) KBr2) KBr ______________________
3)3) Al Al22SS33 ___________ ___________
4) MgO4) MgO ______________________
Learning CheckLearning Check
38
Complete the names of the following Complete the names of the following compounds:compounds:
1)1) NaNa33NN sodium nitridesodium nitride
2)2) KBrKBr potassium bromidepotassium bromide
3)3) AlAl22SS33 aluminumaluminum sulfidesulfide
4)4) MgOMgO magnesium oxidemagnesium oxide
SolutionSolution
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Most Most transitiotransition n elements elements have two have two or more or more positive positive ions.ions.
Ionic Charges of Transition Ionic Charges of Transition MetalsMetals
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Summary of Common IonsSummary of Common Ions
Of the transition metals, silver and zinc are Of the transition metals, silver and zinc are important elements that form only one ion.important elements that form only one ion.
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A. The formula for the ionic A. The formula for the ionic compound of compound of
NaNa+ + and Oand O2-2- is is1) NaO1) NaO 2) Na2) Na22OO 3) NaO3) NaO22
B. The formula of a compound of B. The formula of a compound of aluminum and chlorine isaluminum and chlorine is1) Al1) Al33ClCl 2) AlCl2) AlCl22 3) AlCl3) AlCl33
C. The formula of FeC. The formula of Fe3+3+ and O and O2-2- is is 1) Fe1) Fe33OO22 2) FeO2) FeO33 3) Fe3) Fe22OO33
Learning CheckLearning Check
42
A. The formula for the ionic compound A. The formula for the ionic compound of of
NaNa+ + and Oand O2-2- is is2) Na2) Na22OO
B. The formula of a compound of B. The formula of a compound of aluminum and chlorine isaluminum and chlorine is
3) AlCl3) AlCl33
C. The formula of FeC. The formula of Fe3+3+ and O and O2-2- is is 3) Fe3) Fe22OO33
SolutionSolution
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Naming Compounds with Naming Compounds with Transition MetalsTransition Metals
Transition metals with two different ions Transition metals with two different ions use a Roman numeral following the name use a Roman numeral following the name of the metal to indicate ionic charge.of the metal to indicate ionic charge.
44
Learning CheckLearning Check
Select the correct name for each.Select the correct name for each.A. FeA. Fe22SS33
1) iron sulfide1) iron sulfide 2) iron(II) sulfide2) iron(II) sulfide 3) iron (III) sulfide3) iron (III) sulfide
B. CuSOB. CuSO44
1) copper sulfate1) copper sulfate 2) copper(I) sulfate2) copper(I) sulfate 3) copper (II) sulfate3) copper (II) sulfate
45
SolutionSolution
Select the correct name for each.Select the correct name for each.A. FeA. Fe22SS33
3) iron (III) sulfide3) iron (III) sulfide
B. CuSOB. CuSO44
3) copper (II) sulfate3) copper (II) sulfate
46
Learning CheckLearning Check
The correct formula isThe correct formula is
A. Copper (I) nitrideA. Copper (I) nitride
1) CuN1) CuN 2) CuN2) CuN33 3) Cu 3) Cu33NN
B. Lead (IV) oxideB. Lead (IV) oxide
1) PbO1) PbO22 2) PbO2) PbO 3) Pb 3) Pb22OO44
47
SolutionSolution
The correct formula isThe correct formula is
A. Copper (I) nitrideA. Copper (I) nitride
3) Cu3) Cu33NN
B. Lead (IV) oxideB. Lead (IV) oxide
1) PbO1) PbO22
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4.5 4.5 Covalent BondsCovalent Bonds
4.6 4.6 Naming and Writing Naming and Writing Formulas of Covalent Formulas of Covalent CompoundsCompounds
4.7 4.7 Bond PolarityBond Polarity
Chapter 4 Chapter 4 Compounds and Their BondsCompounds and Their Bonds
49
Covalent bonds form between Covalent bonds form between two nonmetals from Groups 4A, two nonmetals from Groups 4A, 5A, 6A, and 7A.5A, 6A, and 7A.
In a covalent bond, electrons are In a covalent bond, electrons are shared to complete octets.shared to complete octets.
Covalent BondsCovalent Bonds
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Indicate whether a bond between Indicate whether a bond between the following is 1) Ionicthe following is 1) Ionic 2) 2) Covalent Covalent ____A.____A. sodium and oxygensodium and oxygen____B.____B. nitrogen and oxygennitrogen and oxygen
____C. ____C. phosphorus and chlorinephosphorus and chlorine
____D.____D. calcium and sulfurcalcium and sulfur
____E.____E. chlorine and brominechlorine and bromine
Learning CheckLearning Check
51
Indicate whether a bond between Indicate whether a bond between the following is 1) Ionicthe following is 1) Ionic 2) 2) Covalent Covalent
1 1 A. A. sodium and oxygensodium and oxygen
2 2 B. B. nitrogen and oxygennitrogen and oxygen
2 2 C. C. phosphorus and chlorinephosphorus and chlorine
1 1 D. D. calcium and sulfurcalcium and sulfur
2 2 E. E. chlorine and brominechlorine and bromine
SolutionSolution
52
In hydrogen, two hydrogen atoms share In hydrogen, two hydrogen atoms share their electrons to form a covalent bond.their electrons to form a covalent bond.
Each hydrogen atom acquires a stable Each hydrogen atom acquires a stable outer shell of two (2) electrons like outer shell of two (2) electrons like helium (He).helium (He).
HH ++ H H H : H = H H : H = HH = HH = H22
hydrogen moleculehydrogen molecule
HH22, A Covalent Molecule, A Covalent Molecule
53
Diatomic ElementsDiatomic Elements
As As elements, elements, the the following following share share electrons to electrons to form form diatomic, diatomic, covalent covalent molecules.molecules.
54
What is the name of each of the What is the name of each of the following diatomic molecules?following diatomic molecules?
HH22 hydrogenhydrogen
NN22 nitrogennitrogen
ClCl22 ______________________________
OO22 ______________________________
II22 ______________________________
Learning CheckLearning Check
55
What are the names of each of the What are the names of each of the following diatomic molecules?following diatomic molecules?
HH22 hydrogenhydrogen
NN22 nitrogennitrogen
ClCl22 chlorine chlorine
OO22 oxygenoxygen
II22 iodineiodine
SolutionSolution
56
The compound NHThe compound NH33 consists of a N atom consists of a N atom and three H atoms.and three H atoms.
NN and 3 and 3 HH
By sharing electrons to form NHBy sharing electrons to form NH33, the , the electron dot structure is written aselectron dot structure is written as
HH Bonding pairsBonding pairs
H H :: N N :: H H Lone pair of electronsLone pair of electrons
Covalent Bonds in NHCovalent Bonds in NH33
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Number of Covalent BondsNumber of Covalent Bonds
Often, the number of covalent bonds Often, the number of covalent bonds formed by a nonmetal is equal to the formed by a nonmetal is equal to the number of electrons needed to number of electrons needed to complete the octet.complete the octet.
58
Dot Structures and Models of Dot Structures and Models of Some Covalent CompoundsSome Covalent Compounds
59
Multiple BondsMultiple Bonds
Sharing one pair of electrons is a Sharing one pair of electrons is a single bond.single bond.
X X :: X or X X or X–X–X In multiple bonds, two pairs of In multiple bonds, two pairs of
electrons are shared to form a electrons are shared to form a double double bond bond or three pairs of electrons are or three pairs of electrons are shared in a shared in a triple bond.triple bond.
X X : :: : X or X X or X =X=X
X X :: :: :: X or X X or X ≡≡ XX
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In nitrogen, octets are achieved by In nitrogen, octets are achieved by sharing three pairs of electrons.sharing three pairs of electrons.
When three pairs of electrons are When three pairs of electrons are shared, the multiple bond is called a shared, the multiple bond is called a triple bond.triple bond.
octetsoctets N N + +
N N N:::N N:::N
triple bondtriple bond
Multiple Bonds in NMultiple Bonds in N22
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In the name of a In the name of a covalent covalent compound, the compound, the first nonmetal is first nonmetal is named followed by named followed by the name of the the name of the second nonmetal second nonmetal ending in –ide.ending in –ide.
Prefixes indicate Prefixes indicate the number of the number of atoms of each atoms of each element.element.
Naming Covalent CompoundsNaming Covalent Compounds
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Complete the name of each covalent Complete the name of each covalent
compound:compound:
COCO carbon ______oxidecarbon ______oxide
COCO22 carbon _______________carbon _______________
PClPCl33 phosphorus ___________phosphorus ___________
CClCCl44 carbon _______________carbon _______________
NN22OO ____________________________________________
Learning CheckLearning Check
63
Complete the name of each covalent Complete the name of each covalent
compound:compound:
CO CO carbon carbon monmonoxideoxide
COCO22 carbon carbon dioxidedioxide
PClPCl33 phosphorus phosphorus trichloridetrichloride
CClCCl44 carbon carbon tetrachloridetetrachloride
NN22OO dinitrogen monoxidedinitrogen monoxide
SolutionSolution
64
Formulas and Names of Some Formulas and Names of Some Covalent CompoundsCovalent Compounds
65
Select the correct name for each Select the correct name for each compound.compound.
A.A. SiClSiCl44 1) silicon chloride1) silicon chloride2) tetrasilicon chloride2) tetrasilicon chloride3) silicon tetrachloride3) silicon tetrachloride
B. B. PP22OO55 1) phosphorus oxide1) phosphorus oxide2) phosphorus pentoxide2) phosphorus pentoxide3) diphosphorus pentoxide3) diphosphorus pentoxide
C.C. ClCl22OO77 1) dichlorine heptoxide1) dichlorine heptoxide2) dichlorine oxide2) dichlorine oxide3) chlorine heptoxide 3) chlorine heptoxide
Learning CheckLearning Check
66
Select the correct name for each Select the correct name for each compound.compound.
A.A. SiClSiCl44 3) silicon tetrachloride3) silicon tetrachloride
B. B. PP22OO55 3) diphosphorus pentoxide3) diphosphorus pentoxide
C.C. ClCl22OO77 1) dichlorine heptoxide1) dichlorine heptoxide
SolutionSolution
67
Electronegativity is the attraction Electronegativity is the attraction of an atom for shared electrons. of an atom for shared electrons.
The nonmetals have high The nonmetals have high electronegativity values with electronegativity values with fluorine as the highest. fluorine as the highest.
The metals have low The metals have low electronegativity values.electronegativity values.
ElectronegativityElectronegativity
68
Some Electronegativity Values Some Electronegativity Values for Group A Elementsfor Group A Elements
69
The atoms in a The atoms in a nonpolar covalent bond nonpolar covalent bond have electronegativity differences of 0.3 have electronegativity differences of 0.3 or less.or less.
Examples: Examples: Atoms Atoms ElectronegativityElectronegativity Type of Type of
DifferenceDifference Bond Bond N-NN-N 3.0 - 3.0 = 0.03.0 - 3.0 = 0.0 Nonpolar Nonpolar covalentcovalentCl-BrCl-Br 3.0 - 2.8 = 0.23.0 - 2.8 = 0.2 Nonpolar Nonpolar covalentcovalentH-SiH-Si2.1 - 1.8 = 0.32.1 - 1.8 = 0.3 Nonpolar covalent Nonpolar covalent
Nonpolar Covalent BondsNonpolar Covalent Bonds
70
The atoms in a The atoms in a polar covalent bond polar covalent bond have have electronegativity differences of 0.4 to 1.6.electronegativity differences of 0.4 to 1.6.
Examples: Examples: Atoms Atoms ElectronegativityElectronegativity Type of Type of
DifferenceDifference Bond BondO-ClO-Cl 3.5 - 3.0 = 0.53.5 - 3.0 = 0.5 Polar covalent Polar covalentCl-CCl-C 3.0 - 2.5 = 0.53.0 - 2.5 = 0.5 Polar covalent Polar covalentO-S O-S 3.5 - 2.5= 1.03.5 - 2.5= 1.0 Polar covalent Polar covalent
Polar Covalent BondsPolar Covalent Bonds
71
Comparing Nonpolar and Comparing Nonpolar and Polar Covalent BondsPolar Covalent Bonds
72
Ionic BondsIonic Bonds
The atoms in an The atoms in an ionic bond ionic bond have have electronegativity differences of 1.7 or electronegativity differences of 1.7 or more.more.
Examples: Examples: Atoms Atoms ElectronegativityElectronegativity Type Type ofof DifferenceDifference BondBondCl-KCl-K 3.0 – 0.8 3.0 – 0.8 = 2.2= 2.2 IonicIonicN-NaN-Na 3.0 – 0.9 3.0 – 0.9 = 2.1= 2.1 IonicIonicS-CsS-Cs2.5 – 0.72.5 – 0.7 = 1.8= 1.8 Ionic Ionic
73
Range of Bond TypesRange of Bond Types
74
Predicting Bond TypePredicting Bond Type
75
Identify the type of bond between Identify the type of bond between the following asthe following as
1) nonpolar covalent 1) nonpolar covalent
2) polar covalent 2) polar covalent
3) ionic3) ionic A. K-NA. K-N
B. N-OB. N-O
C. Cl-ClC. Cl-Cl
Learning CheckLearning Check
76
A. K-NA. K-N3) ionic3) ionic
B. N-OB. N-O2) polar covalent2) polar covalent
C. Cl-ClC. Cl-Cl1) nonpolar covalent 1) nonpolar covalent
SolutionSolution
77
4.8 Polyatomic Ions4.8 Polyatomic Ions
Chapter 4 Chapter 4 Compounds and Their BondsCompounds and Their Bonds
78
A polyatomic ion is a group of two or more A polyatomic ion is a group of two or more atoms that has an overall ionic charge.atoms that has an overall ionic charge.
Some examples of polyatomic ions areSome examples of polyatomic ions are
NHNH44++ ammoniumammonium OHOH - - hydroxide hydroxide
NONO33-- nitratenitrate NONO2 2
-- nitrite nitrite
COCO332 -2 - carbonatecarbonate POPO44
3 - 3 - phosphatephosphate
HCOHCO33 - - hydrogen carbonate (bicarbonate)hydrogen carbonate (bicarbonate)
Polyatomic IonsPolyatomic Ions
79
Common Polyatomic IonsCommon Polyatomic Ions
80
Formulas with Polyatomic IonsFormulas with Polyatomic Ions
The formula of an ionic compound The formula of an ionic compound containing a polyatomic ion is written to containing a polyatomic ion is written to make the overall charge equal zero (0).make the overall charge equal zero (0).NaNa++ and NO and NO33
- - NaNONaNO33
When two or more polyatomic ions are When two or more polyatomic ions are needed, the polyatomic ion is enclosed in needed, the polyatomic ion is enclosed in parentheses.parentheses.polyatomic ionpolyatomic ion
MgMg2+2+ and NO and NO3 3 - - MgMg(NO(NO33))22
subscript 2 for charge balancesubscript 2 for charge balance
81
Some Compounds with Some Compounds with Polyatomic IonsPolyatomic Ions
82
Select the correct formula for each:Select the correct formula for each:A. Aluminum nitrate A. Aluminum nitrate 1) AlNO1) AlNO3 3 2) Al(NO)2) Al(NO)33 3) Al(NO3) Al(NO33))33
B. Copper(II) nitrateB. Copper(II) nitrate 1) CuNO1) CuNO33 2) Cu(NO2) Cu(NO33))22 3) Cu3) Cu22(NO(NO33))
C. Iron (III) hydroxideC. Iron (III) hydroxide 1) FeOH1) FeOH 2) Fe2) Fe33OHOH 3) Fe(OH)3) Fe(OH)33
D. Tin(IV) hydroxideD. Tin(IV) hydroxide 1) Sn(OH)1) Sn(OH)44 2) Sn(OH)2) Sn(OH)22 3) 3) SnSn44(OH)(OH)
Learning CheckLearning Check
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Select the correct formula for each:Select the correct formula for each:A. A. Aluminum nitrate Aluminum nitrate 3) Al(NO3) Al(NO33))33
B. B. Copper(II) nitrateCopper(II) nitrate 2) Cu(NO2) Cu(NO33))22
C. C. Iron (III) hydroxideIron (III) hydroxide 3) Fe(OH)3) Fe(OH)33
D. D. Tin(IV) hydroxideTin(IV) hydroxide 1) Sn(OH)1) Sn(OH)44
SolutionSolution
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For compounds with polyatomic ions, For compounds with polyatomic ions, the positive ion is named first the positive ion is named first followed by the name of the followed by the name of the polyatomic ion.polyatomic ion.NaNaNONO33 sodium sodium nitratenitrateKK22SOSO44 potassium potassium sulfatesulfateAlAl(HCO(HCO33))33 aluminumaluminum bicarbonatebicarbonate
oror aluminumaluminum hydrogen hydrogen carbonatecarbonate(NH(NH44))33POPO44 ammonium phosphateammonium phosphate
Naming Compounds with Naming Compounds with Polyatomic IonsPolyatomic Ions
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Match each formula with the correct Match each formula with the correct name:name:
A.A. NaNa22COCO33 1) magnesium sulfite 1) magnesium sulfite
MgSOMgSO33 2) magnesium sulfate2) magnesium sulfate
MgSOMgSO44 3) sodium carbonate 3) sodium carbonate
B.B. Ca(HCO Ca(HCO33))22 1) calcium carbonate1) calcium carbonate
CaCOCaCO33 2) calcium phosphate2) calcium phosphate
CaCa33(PO(PO44))2 2 3) calcium bicarbonate3) calcium bicarbonate
Learning CheckLearning Check
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A.A. NaNa22COCO33 3) sodium carbonate 3) sodium carbonate
MgSOMgSO33 1) magnesium sulfite1) magnesium sulfite
MgSOMgSO44 2) magnesium sulfate2) magnesium sulfate
B.B. Ca(HCO Ca(HCO33))22 3) calcium 3) calcium bicarbonatebicarbonate CaCOCaCO33 1) calcium carbonate1) calcium carbonate
CaCa33(PO(PO44))2 2 2) calcium phosphate2) calcium phosphate
SolutionSolution
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Summary of Naming Summary of Naming CompoundsCompounds
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Naming RulesNaming Rules
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Naming Rules (continued)Naming Rules (continued)
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Learning CheckLearning Check
Name each of the following compounds:Name each of the following compounds:
A.A. Mg(NOMg(NO33))22
B.B. CuClCuCl22
C.C. NN22OO44
D.D. FeFe22(SO(SO44))33
E.E. BaBa33(PO(PO44))22
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SolutionSolution
Name each of the following compounds:Name each of the following compounds:
A.A. Mg(NOMg(NO33))22 magnesium nitratemagnesium nitrate
B.B. CuClCuCl22 copper(II) chloridecopper(II) chloride
C.C. NN22OO44 dinitrogen tetroxidedinitrogen tetroxide
D.D. FeFe22(SO(SO44))33iron(III) sulfateiron(III) sulfate
E.E. BaBa33(PO(PO44))22 barium phosphatebarium phosphate
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Learning CheckLearning Check
Write the correct formula for each:Write the correct formula for each:
A.A. potassium sulfidepotassium sulfide
B.B. calcium carbonatecalcium carbonate
C.C. sodium phosphitesodium phosphite
D.D. iron(III) oxideiron(III) oxide
E.E. iron (II) nitrateiron (II) nitrate
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SolutionSolution
Write the correct formula for each:Write the correct formula for each:
A.A. potassium sulfidepotassium sulfide KK22SS
B.B. calcium carbonatecalcium carbonate CaCOCaCO33
C.C. sodium phosphitesodium phosphite NaNa33POPO33
D.D. iron(III) oxideiron(III) oxide FeFe22OO33
E.E. iron (II) nitrateiron (II) nitrate Fe(NOFe(NO33))22
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Chapter 4 Chapter 4 Compounds and Their BondsCompounds and Their Bonds
4.9 4.9 Shapes of Molecules Shapes of Molecules
4.104.10 Polar and Nonpolar Polar and Nonpolar MoleculesMolecules
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VSEPRVSEPR
The shape of a molecule is predicted The shape of a molecule is predicted from the geometry of the electrons from the geometry of the electrons pairs around the central atom.pairs around the central atom.
In the In the valence-shell electron-pair valence-shell electron-pair repulsion theory (VSEPR),repulsion theory (VSEPR), the the electron pairs are arranged as far electron pairs are arranged as far apart as possible to give the least apart as possible to give the least amount of repulsion of the negatively amount of repulsion of the negatively charged electrons.charged electrons.
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Two Electron PairsTwo Electron Pairs
In a molecule of BeClIn a molecule of BeCl22, there are two , there are two bonding pairs around the central bonding pairs around the central atom Be. (Be is an exception to the atom Be. (Be is an exception to the octet rule.)octet rule.)
The arrangement of two electron pairs The arrangement of two electron pairs to minimize their repulsion is 180to minimize their repulsion is 180° ° or opposite each other.or opposite each other.
The shape of the molecule is The shape of the molecule is linear.linear.
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Two Electron Pairs with Two Electron Pairs with Double BondsDouble Bonds
The electron-dot structure for COThe electron-dot structure for CO2 2 consists of two double bonds to the consists of two double bonds to the central atom C. central atom C.
Because the electrons in a double bond Because the electrons in a double bond are held together, a double bond is are held together, a double bond is counted as a single unit.counted as a single unit.
Repulsion is minimized when the double Repulsion is minimized when the double bonds are placed opposite each other at bonds are placed opposite each other at 180180° to give a ° to give a linear shape.linear shape.
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Three Electron PairsThree Electron Pairs
In BFIn BF33, there are 3 electron pairs around , there are 3 electron pairs around the central atom B. (B is an exception to the the central atom B. (B is an exception to the octet rule.)octet rule.)
Repulsion is minimized by placing three Repulsion is minimized by placing three electron pairs in a plane at angles of 120electron pairs in a plane at angles of 120°, °, which is a which is a trigonal planar trigonal planar arrangement.arrangement.
The shape with three bonded atoms is The shape with three bonded atoms is trigonal planartrigonal planar..
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Two Bonding Pairs and A Two Bonding Pairs and A Nonbonding PairNonbonding Pair
In SOIn SO22, there are 3 electron units around , there are 3 electron units around the central atom S. the central atom S.
Two electron units are bonded to atoms Two electron units are bonded to atoms and one electron pair is a nonbonding and one electron pair is a nonbonding pair.pair.
Repulsion is minimized by placing three Repulsion is minimized by placing three electron pairs in a plane at angles of 120electron pairs in a plane at angles of 120°, °, which is which is trigonal planar.trigonal planar.
The shape with two bonded atoms is The shape with two bonded atoms is bent.bent.
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Learning CheckLearning Check
The shape of a molecule of NThe shape of a molecule of N22O (N N O) O (N N O) isis
1) linear1) linear
2) trigonal planar2) trigonal planar
3) bent (1203) bent (120°)°)
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SolutionSolution
The shape of a molecule of NThe shape of a molecule of N22O (N N O) isO (N N O) is1) linear1) linear
The electron-dot structure uses 5 e for The electron-dot structure uses 5 e for each N and 6 e for O (16 e total) has each N and 6 e for O (16 e total) has octets using two double bond to the octets using two double bond to the central N and one nonbonding pair. The central N and one nonbonding pair. The shape with two bonded atoms is linearshape with two bonded atoms is linear..
• • • •• • • •
:: N N :::: N N :::: O O ::
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Four Electron PairsFour Electron Pairs
In CHIn CH44, there are 4 electron pairs , there are 4 electron pairs around the central atom C. around the central atom C.
Repulsion is minimized by placing Repulsion is minimized by placing four electron pairs at angles of 109four electron pairs at angles of 109°, °, which is a which is a tetrahedral tetrahedral arrangement.arrangement.
The shape with four bonded atoms is The shape with four bonded atoms is called called tetrahedraltetrahedral..
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Three Bonding Atoms and One Three Bonding Atoms and One Nonbonding PairNonbonding Pair
In NHIn NH33, there are 4 electron pairs around the , there are 4 electron pairs around the N. N.
Three pairs are bonded to atoms and one is a Three pairs are bonded to atoms and one is a nonbonding pair.nonbonding pair.
Repulsion is minimized by placing four Repulsion is minimized by placing four electron pairs at angles of 109electron pairs at angles of 109°, which is a °, which is a tetrahedral tetrahedral arrangement.arrangement.
The shape with three bonded atoms is The shape with three bonded atoms is pyramidalpyramidal..
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Two Bonding Atoms and Two Two Bonding Atoms and Two Lone PairsLone Pairs
In HIn H22O, there are 4 electron pairs O, there are 4 electron pairs around O. around O.
Two pairs are bonded to atoms and two Two pairs are bonded to atoms and two are nonbonding pairs.are nonbonding pairs.
Repulsion is minimized by placing four Repulsion is minimized by placing four electron pairs at angles of 109electron pairs at angles of 109° called ° called a a tetrahedral tetrahedral arrangement.arrangement.
The shape with two bonded atoms is The shape with two bonded atoms is called called bentbent..
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Some Steps Using VSEPR to Some Steps Using VSEPR to Predict ShapePredict Shape
Draw the electron dot structure.Draw the electron dot structure. Count the electron pairs around the Count the electron pairs around the
central atom.central atom. Arrange the electron pairs to Arrange the electron pairs to
minimize repulsion.minimize repulsion. Determine the shape using the Determine the shape using the
number of bonded atoms in the number of bonded atoms in the electron arrangement. electron arrangement.
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Summary of Electron Summary of Electron Arrangements and ShapesArrangements and Shapes
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Learning CheckLearning Check
Use VSEPR theory to determine the Use VSEPR theory to determine the shape of the following molecules or shape of the following molecules or ions.ions.
1) tetrahedral 1) tetrahedral 2) pyramidal 2) pyramidal3) bent3) bent
A. PFA. PF33
B. HB. H22SS
C. CClC. CCl44
D. POD. PO443-3-
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SolutionSolution
Use VSEPR theory to determine the Use VSEPR theory to determine the shape of the following molecules or shape of the following molecules or ions.ions.
1) tetrahedral1) tetrahedral 2) pyramidal2) pyramidal 3) 3) bentbent
A. A. PFPF33 2) pyramidal2) pyramidal
B.B. HH22SS 3) bent3) bent
C. C. CClCCl44 1) tetrahedral1) tetrahedral
D. D. POPO443-3- 1) tetrahedral1) tetrahedral
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Polar MoleculesPolar Molecules
A A polar molecule polar molecule contains polar contains polar bonds.bonds.
The separation of positive and The separation of positive and negative charge is called a dipole.negative charge is called a dipole.
In a polar molecule, dipoles do not In a polar molecule, dipoles do not cancel.cancel.
++ -- • •• •
HH–Cl–Cl Cl–N–Cl Cl–N–Cl dipoledipole ClCl
dipoles do not canceldipoles do not cancel
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Nonpolar MoleculesNonpolar Molecules
A A nonpolar moleculenonpolar molecule contains nonpolar contains nonpolar bondsbonds
ClCl–Cl–Cl H–HH–H
or a symmetrical arrangement of polar or a symmetrical arrangement of polar bonds.bonds.
O=C=OO=C=O ClCl
Cl–C–Cl Cl–C–Cl ClCl
dipoles canceldipoles cancel
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Learning CheckLearning Check
Identify each of the following molecules Identify each of the following molecules as as
1) polar or 2) nonpolar. Explain.1) polar or 2) nonpolar. Explain.
A. PBrA. PBr33
B. HBrB. HBr
C. BrC. Br22
D. SiBrD. SiBr44
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SolutionSolution
Identify each of the following molecules Identify each of the following molecules as as
1) polar or 2) nonpolar. Explain.1) polar or 2) nonpolar. Explain.
A. PBrA. PBr33 1) polar; pyramidal1) polar; pyramidal
B. HBrB. HBr 1) polar; polar bond1) polar; polar bond
C. BrC. Br22 2) nonpolar, nonpolar bond2) nonpolar, nonpolar bond
D. SiBrD. SiBr44 2) nonpolar; dipoles cancel2) nonpolar; dipoles cancel