Chapter 6 Chemical Names and Formulas. Section 6.1 Introduction to Chemical Bonding OBJECTIVES: OBJECTIVES: Distinguish between ionic and molecular compounds

Chapter 6Chapter 6Chemical Names and Chemical Names and

FormulasFormulas

Section 6.1Section 6.1Introduction to Chemical Introduction to Chemical

BondingBondingOBJECTIVES:OBJECTIVES:

Distinguish between ionic and molecular Distinguish between ionic and molecular compounds.compounds.

Section 6.1Section 6.1Introduction to Chemical Introduction to Chemical

BondingBondingOBJECTIVES:OBJECTIVES:

Define cation and anion, and relate Define cation and anion, and relate them to metal and nonmetal.them to metal and nonmetal.

Molecules and Molecular Molecules and Molecular CompoundsCompounds

About 100 different elementsAbout 100 different elementsMillions of compounds from themMillions of compounds from themNaming is essential in chemistryNaming is essential in chemistryNoble gases, such as He and NeNoble gases, such as He and NeIsolated atoms- monatomic, they Isolated atoms- monatomic, they

consist of single atomsconsist of single atoms


Molecule- smallest electrically neutral Molecule- smallest electrically neutral unit, still has properties of the unit, still has properties of the substancesubstance

Made from only nonmetalsMade from only nonmetalsCan be from one element- OCan be from one element- O22

Can make a compound- COCan make a compound- CO22


Properties of molecular compoundsProperties of molecular compoundsLow melting and boiling pointsLow melting and boiling pointsUsually gas or liquidUsually gas or liquidComposed of two or more Composed of two or more

nonmetalsnonmetalsOO22, O, O33, H, H22OO

Systematic NamingSystematic Naming

There are too many compounds to There are too many compounds to remember the names of them all.remember the names of them all.

Compound is made of two or more Compound is made of two or more elements.elements.

Put together atoms.Put together atoms.Name should tell us how many and Name should tell us how many and

what type of atoms.what type of atoms.

Atoms and ionsAtoms and ions

AtomsAtoms are electrically neutral. are electrically neutral.Same number of protons and electrons.Same number of protons and electrons. IonsIons are atoms, or groups of atoms, with a are atoms, or groups of atoms, with a

charge (positive or negative)charge (positive or negative)Different numbers of protons and Different numbers of protons and

electrons.electrons.Only electrons can move.Only electrons can move.Gain or lose electrons.Gain or lose electrons.

AnionAnion

A negative ion.A negative ion.Has Has gainedgained electrons. electrons.Nonmetals can gainNonmetals can gain electrons. electrons.Charge is written as a superscript on the Charge is written as a superscript on the

right.right.

F-Has gained one electron (-ide is new ending= fluoride)

O2- Gained two electrons (oxide)

Cations Positive ions. Formed by losing electrons. More protons than electrons. Metals can lose electrons

K+ Has lost one electron (no name change for positive ions)

Ca2+ Has lost two electrons

Ionic CompoundsIonic Compounds

Ionic compoundsIonic compounds- from joining - from joining metal metal cations and nonmetal anionscations and nonmetal anions- they - they are are electrically neutralelectrically neutral

Usually solid crystalsUsually solid crystalsMelt at high temperaturesMelt at high temperatures

Two Types of CompoundsTwo Types of Compounds

Molecular compoundsMolecular compoundsMade of molecules.Made of molecules.Made by joining Made by joining nonmetalnonmetal atoms atoms

together into molecules.together into molecules.


Ionic CompoundsIonic CompoundsMade of cations and anions.Made of cations and anions.Metals and nonmetalsMetals and nonmetals..The electrons lost by the cation are The electrons lost by the cation are

gained by the anion.gained by the anion.The cation and anions surround each The cation and anions surround each

other.other.Smallest piece is a Smallest piece is a FORMULA UNIT.FORMULA UNIT.


Smallest piece

Melting Point

State

Types of elements

Formula Unit Molecule

Metal and Nonmetal

Nonmetals

solidSolid, liquid or gas

High >300ºC Low <300ºC

Ionic Molecular

Section 6.2Section 6.2Representing Chemical Representing Chemical

CompoundsCompoundsOBJECTIVES:OBJECTIVES:

Distinguish among chemical formulas, Distinguish among chemical formulas, molecular formulas, and formula units.molecular formulas, and formula units.

Section 6.2Section 6.2Representing Chemical Representing Chemical

CompoundsCompoundsOBJECTIVES:OBJECTIVES:

Use experimental data to show that a Use experimental data to show that a compound obeys the law of definite compound obeys the law of definite proportions.proportions.

Chemical FormulasChemical Formulas

Shows the Shows the kindkind and and numbernumber of atoms of atoms in the smallest piece of a substance.in the smallest piece of a substance.

Molecular formulaMolecular formula- number and kinds - number and kinds of atoms in a molecule.of atoms in a molecule.

COCO22

CC66HH1212OO66

Chemical FormulasChemical Formulas

More than one atom? –use a More than one atom? –use a subscript (Hsubscript (H22O)O)

There are 7 There are 7 diatomicdiatomic elements elementsHydrogen (HHydrogen (H22), Nitrogen (N), Nitrogen (N22), ),

Oxygen (OOxygen (O22), Fluorine (F), Fluorine (F22), Chlorine ), Chlorine

(Cl(Cl22), Bromine (Br), Bromine (Br22), and Iodine (I), and Iodine (I22))Remember: “Br I N Cl H O F”Remember: “Br I N Cl H O F”

Ionic CompoundsIonic Compounds

This formula represents not a This formula represents not a molecule, but a molecule, but a formula unitformula unit

The smallest whole number ratio of The smallest whole number ratio of atoms in an ionic compound.atoms in an ionic compound.

Ions surround each other so you can’t Ions surround each other so you can’t say which is hooked to which. (p. say which is hooked to which. (p. 140)140)

Some Laws:Some Laws:

1. 1. Law of Definite ProportionsLaw of Definite Proportions- in a - in a sample of a chemical compound, the sample of a chemical compound, the masses of the elements are always in masses of the elements are always in the same proportions.the same proportions.

HH22O (water) and HO (water) and H22OO22 (hydrogen (hydrogen

peroxide)peroxide)

Some Laws:Some Laws:

2. 2. Law of Multiple ProportionsLaw of Multiple Proportions- - Dalton stated that whenever two Dalton stated that whenever two elements form more than one elements form more than one compound, the different masses of compound, the different masses of one element that combine with the one element that combine with the same mass of the other element same mass of the other element are in the ratio of small whole are in the ratio of small whole numbers.numbers.

Figure 6.11, p. 141Figure 6.11, p. 141

Section 6.3Section 6.3Ionic ChargesIonic Charges

OBJECTIVES:OBJECTIVES:Use the periodic table to determine the Use the periodic table to determine the

charge on an ion.charge on an ion.

Section 6.3Section 6.3Ionic ChargesIonic Charges

OBJECTIVES:OBJECTIVES:Define a polyatomic ion, and give the Define a polyatomic ion, and give the

names and formulas of the most names and formulas of the most common polyatomic ions.common polyatomic ions.

Charges on ionsCharges on ions

For most of the Group A elements, For most of the Group A elements, the Periodic Table can tell what the Periodic Table can tell what kind of ion they will form from their kind of ion they will form from their location; location; monatomicmonatomic ions ions

Elements in the same group have Elements in the same group have similar properties.similar properties.

Including the charge when they are Including the charge when they are ions.ions.

2+

1+

3+ 3- 2- 1-

What about the others?What about the others?

Groups 4A and 0 do not usually form Groups 4A and 0 do not usually form ions (in fact, Group 0 rarely forms ions (in fact, Group 0 rarely forms compounds!)compounds!)

Many transition metals have Many transition metals have more more than one than one common ionic chargecommon ionic charge

Naming ionsNaming ions

Two methods if more than one Two methods if more than one charge is possible:charge is possible:1. Stock system – uses roman 1. Stock system – uses roman

numerals in parenthesis to numerals in parenthesis to indicate the numerical valueindicate the numerical value

2. Classical method – uses root 2. Classical method – uses root word with suffixes (-ous, -ic)word with suffixes (-ous, -ic)Does not give true valueDoes not give true value

Naming ionsNaming ions

We will use the Stock system.We will use the Stock system.Cation- if the charge is always the Cation- if the charge is always the

same (Group A) just write the name of same (Group A) just write the name of the metal.the metal.

Transition metals can have more than Transition metals can have more than one type of charge.one type of charge.

Indicate the charge with roman Indicate the charge with roman numerals in parenthesis (Table 6.3, numerals in parenthesis (Table 6.3, p.144)p.144)

Name theseName these

NaNa++ CaCa2+2+ AlAl3+3+ FeFe3+3+ FeFe2+2+ PbPb2+2+ LiLi++

Write Formulas for theseWrite Formulas for these

Potassium ionPotassium ionMagnesium ion Magnesium ion Copper (II) ionCopper (II) ionChromium (VI) ionChromium (VI) ionBarium ionBarium ionMercury (II) ionMercury (II) ion

Naming AnionsNaming Anions

Anions are always the same chargeAnions are always the same chargeChange the element ending to – Change the element ending to – ideideFF-- Fluor Fluorineine


Anions are always the same chargeAnions are always the same chargeChange the element ending to – Change the element ending to – ideideFF-- Fluor Fluorinin


Anions are always the same chargeAnions are always the same chargeChange the element ending to – Change the element ending to – ideideFF-- Fluor Fluorii


Anions are always the same chargeAnions are always the same chargeChange the element ending to – Change the element ending to – ideideFF-- Fluor Fluor


Anions are always the same chargeAnions are always the same chargeChange the element ending to – Change the element ending to – ideideFF-- Fluor Fluorii


Anions are always the same chargeAnions are always the same chargeChange the element ending to – ideChange the element ending to – ideFF-- Fluor Fluoridid


Anions are always the same chargeAnions are always the same chargeChange the element ending to – Change the element ending to – ideideFF-- Fluor Fluorideide


ClCl-- NN3-3- BrBr-- OO2-2-

GaGa3+3+

Write theseWrite these

Sulfide ionSulfide ioniodide ioniodide ionphosphide ionphosphide ionStrontium ionStrontium ion

Exceptions:Exceptions:Some of the transition metals have Some of the transition metals have

only one ionic charge:only one ionic charge:Do not use roman numerals for Do not use roman numerals for

these:these:SilverSilver is always 1+ ( is always 1+ (AgAg++))CadmiumCadmium and and ZincZinc are always are always

2+ (2+ (CdCd2+2+ and and ZnZn2+2+))Note Fig. 6.13, p. 145Note Fig. 6.13, p. 145

Polyatomic ionsPolyatomic ionsGroups of atoms that stay together and Groups of atoms that stay together and

have a charge.have a charge.Learn these - Table 6.4, p.147Learn these - Table 6.4, p.147

Acetate Acetate CC22HH33OO22--

Nitrate Nitrate NONO33--

Nitrite Nitrite NONO22--

Hydroxide Hydroxide OHOH-- and Cyanide and Cyanide CNCN-- Permanganate Permanganate MnOMnO44

--

Polyatomic ionsPolyatomic ionsSulfate Sulfate SOSO44

2-2-

Sulfite Sulfite SOSO332-2-

Carbonate Carbonate COCO332-2-

Chromate Chromate CrOCrO442-2-

Dichromate Dichromate CrCr22OO772-2-

Phosphate Phosphate POPO443-3-

Phosphite Phosphite POPO333-3-

Ammonium Ammonium NHNH44++

Section 6.4Section 6.4Ionic CompoundsIonic Compounds

OBJECTIVES:OBJECTIVES:Apply the rules for naming and writing Apply the rules for naming and writing

formulas for binary ionic compounds.formulas for binary ionic compounds.

Section 6.4Section 6.4Ionic CompoundsIonic Compounds

OBJECTIVES:OBJECTIVES:Apply the rules for naming and writing Apply the rules for naming and writing

formulas for ternary ionic compounds.formulas for ternary ionic compounds.

Naming Binary Ionic CompoundsNaming Binary Ionic CompoundsBinaryBinary Compounds - 2 elements. Compounds - 2 elements. Ionic - a cation and an anion.Ionic - a cation and an anion.To write the names, just name the two To write the names, just name the two

ions.ions.Easy with Representative elements Easy with Representative elements

(which are Group A elements)(which are Group A elements)NaCl = NaCl = NaNa++ ClCl-- = sodium chloride = sodium chloride

MgBrMgBr22 = = MgMg2+2+ BrBr-- = magnesium bromide= magnesium bromide

Naming Binary Ionic CompoundsNaming Binary Ionic Compounds

The problem comes with the The problem comes with the transition metals.transition metals.

Need to figure out their charges.Need to figure out their charges.The compound must be neutral.The compound must be neutral.same number of + and – charges.same number of + and – charges.Use the anion to determine the Use the anion to determine the

charge on the positive ion.charge on the positive ion.


Write the name of CuOWrite the name of CuONeed the charge of CuNeed the charge of CuO is 2-O is 2-copper must be 2+copper must be 2+Copper (II) oxideCopper (II) oxideName CoClName CoCl33 Cl is 1- and there are three of them = 3-Cl is 1- and there are three of them = 3-Co must be 3+ Cobalt (III) chlorideCo must be 3+ Cobalt (III) chloride


Write the name of CuWrite the name of Cu22S.S.

Since S is 2-, the CuSince S is 2-, the Cu22 must be 2+, so must be 2+, so

each one is 1+.each one is 1+.copper (I) sulfidecopper (I) sulfideFeFe22OO33 Each O is 2- 3 x -2 = -6Each O is 2- 3 x -2 = -62 Fe must = 6+, so each is 3+.2 Fe must = 6+, so each is 3+. iron (III) oxideiron (III) oxide


Write the names of the followingWrite the names of the following KClKCl NaNa33NN

CrNCrN

ScSc33PP22

PbOPbO

PbOPbO22

NaNa22SeSe

Ternary Ionic Compounds Ternary Ionic Compounds

These will have polyatomic ionsThese will have polyatomic ionsAt least three elementsAt least three elementsname the ionsname the ionsNaNONaNO33

CaSOCaSO44

CuSOCuSO33

(NH(NH44))22OO

Ternary Ionic CompoundsTernary Ionic Compounds

LiCNLiCNFe(OH)Fe(OH)33

(NH(NH44))22COCO33

NiPONiPO44

Writing FormulasWriting Formulas

The charges have to add up to The charges have to add up to zero.zero.

Get charges on pieces.Get charges on pieces.Cations from name on table.Cations from name on table.Anions from table or polyatomic.Anions from table or polyatomic.Balance the charges by adding Balance the charges by adding

subscripts.subscripts.Put polyatomics in parenthesis.Put polyatomics in parenthesis.

Writing FormulasWriting Formulas

Write the formula for calcium chloride.Write the formula for calcium chloride.Calcium is Calcium is CaCa2+2+ Chloride is Chloride is ClCl-- CaCa2+2+ Cl Cl-- would have a 1+ charge. would have a 1+ charge.Need another Need another ClCl-- CaCa2+2+ Cl Cl22

1-1- (use criss-cross method) (use criss-cross method)

Write the formulas for theseWrite the formulas for these

Lithium sulfideLithium sulfide tin (II) oxidetin (II) oxide tin (IV) oxidetin (IV) oxideMagnesium fluorideMagnesium fluorideCopper (II) sulfateCopper (II) sulfate Iron (III) phosphideIron (III) phosphidegallium nitrategallium nitrate Iron (III) sulfideIron (III) sulfide

Write the formulas for theseWrite the formulas for these

Ammonium chlorideAmmonium chlorideammonium sulfideammonium sulfidebarium nitratebarium nitrate

Things to look forThings to look for

If cations have ( ), the number in If cations have ( ), the number in parenthesis is their charge.parenthesis is their charge.

If anions end in If anions end in -ide-ide they are probably they are probably off the periodic table (Monoatomic)off the periodic table (Monoatomic)

If anion ends in If anion ends in -ate-ate or or -ite-ite it is it is polyatomicpolyatomic

Section 6.5Section 6.5Molecular Compounds and Molecular Compounds and

AcidsAcidsOBJECTIVES:OBJECTIVES:

Apply the rules for naming and writing Apply the rules for naming and writing formulas for binary molecular formulas for binary molecular compounds.compounds.

Section 6.5Section 6.5Molecular Compounds and Molecular Compounds and

AcidsAcidsOBJECTIVES:OBJECTIVES:

Name and write formulas for common Name and write formulas for common acids.acids.

Molecular compoundsMolecular compounds

made of just made of just nonmetalsnonmetalssmallest piece is a smallest piece is a moleculemoleculecan’t be held together because of can’t be held together because of

opposite charges.opposite charges.can’t use charges to figure out how can’t use charges to figure out how

many of each atommany of each atom

Molecular are easier!Molecular are easier!

Ionic compounds use charges to Ionic compounds use charges to determine how many of each.determine how many of each.Have to figure out charges.Have to figure out charges.Have to figure out numbers.Have to figure out numbers.

Molecular compounds Molecular compounds name tellsname tells youyou the number of atoms.the number of atoms.

Uses Uses prefixesprefixes to tell you the number to tell you the number

Prefixes (Table 6.5, p.159)Prefixes (Table 6.5, p.159)

1 = mono-1 = mono-2 = di-2 = di-3 = tri-3 = tri-4 = tetra-4 = tetra-5 = penta-5 = penta-6 = hexa-6 = hexa-7 = hepta-7 = hepta-8 = octa- 8 = octa-

PrefixesPrefixes

9 = nona-9 = nona-10 = deca-10 = deca-To write the name, write two words:To write the name, write two words:

PrefixesPrefixes


Prefix name Prefix name -ide

PrefixesPrefixes


One exception is we don’t write mono- if One exception is we don’t write mono- if there is only one of the first element.there is only one of the first element.


PrefixesPrefixes

9 = nona-9 = nona- 10 = deca-10 = deca- To write the name, write two words:To write the name, write two words: One exception is we don’t write mono- if One exception is we don’t write mono- if

there is only one of the first element.there is only one of the first element. No double vowels when writing names No double vowels when writing names

(oa oo)(oa oo)


Name TheseName These

NN22OO

NONO22

ClCl22OO77

CBrCBr44

COCO22

BaClBaCl22

Write formulas for theseWrite formulas for these

diphosphorus pentoxidediphosphorus pentoxidetetraiodine nonoxidetetraiodine nonoxidesulfur hexafluoridesulfur hexafluoridenitrogen trioxidenitrogen trioxidecarbon tetrahydridecarbon tetrahydridephosphorus trifluoridephosphorus trifluoridealuminum chloridealuminum chloride

AcidsAcids

Writing names and FormulasWriting names and Formulas

AcidsAcids

Compounds that give off hydrogen Compounds that give off hydrogen ions when dissolved in water.ions when dissolved in water.

Must have H in them.Must have H in them.will always be some H next to an will always be some H next to an

anion.anion.The The anionanion determines the name. determines the name.

Naming acidsNaming acids

If the anion attached to hydrogen If the anion attached to hydrogen ends in ends in -ide-ide, put the prefix , put the prefix hydro- hydro- and and change -change -ideide to to -ic acid-ic acid

HCl - hydrogen ion and chlorHCl - hydrogen ion and chlorideide ion ionhydrohydrochlorchloric acidic acidHH22S hydrogen ion and sulfS hydrogen ion and sulfideide ion ionhydrohydrosulfursulfuric acidic acid

Naming AcidsNaming Acids

If the anion has oxygen in it, then it If the anion has oxygen in it, then it ends in -ate of -iteends in -ate of -ite

change the suffix change the suffix -ate -ate to to -ic acid -ic acid (use no (use no prefix)prefix)

HNOHNO33 Hydrogen and nitr Hydrogen and nitrateate ions ionsNitrNitric acidic acidchange the suffix change the suffix -ite -ite to to -ous acid-ous acidHNOHNO22 Hydrogen and nitr Hydrogen and nitriteite ions ionsNitrNitrous acidous acid


HFHFHH33PP

HH22SOSO44

HH22SOSO33 HCNHCNHH22CrOCrO44

Writing Acid FormulasWriting Acid Formulas

Hydrogen will always be firstHydrogen will always be firstname will tell you the anionname will tell you the anionmake the charges cancel out.make the charges cancel out.Starts with hydro?- no oxygen, -ideStarts with hydro?- no oxygen, -ideno hydro?, no hydro?, -ate -ate comes from comes from -ic-ic, , -ite -ite

comes from comes from -ous-ous

Write formulas for theseWrite formulas for these

hydroiodic acidhydroiodic acidacetic acidacetic acidcarbonic acidcarbonic acidphosphorous acidphosphorous acidhydrobromic acidhydrobromic acid

Section 6.6Section 6.6Summary of Naming and Summary of Naming and

Formula WritingFormula WritingOBJECTIVES:OBJECTIVES:

Use the flowchart in Figure 6.21 to write Use the flowchart in Figure 6.21 to write the name of a compound when given its the name of a compound when given its chemical formula.chemical formula.

Section 6.6Section 6.6Summary of Naming and Summary of Naming and

Formula WritingFormula WritingOBJECTIVES:OBJECTIVES:

Use the flowchart in Figure 6.23 to write Use the flowchart in Figure 6.23 to write a chemical formula when given the a chemical formula when given the name of a compound.name of a compound.

Helpful to remember...Helpful to remember...

1. In an ionic compound, the net ionic 1. In an ionic compound, the net ionic charge is charge is zero zero (criss-cross method)(criss-cross method)

2. An 2. An -ide-ide ending generally indicates a ending generally indicates a binary compoundbinary compound

3. An 3. An -ite-ite or or -ate-ate ending means there ending means there is a polyatomic ion that has oxygenis a polyatomic ion that has oxygen

4. 4. PrefixesPrefixes generally mean molecular; generally mean molecular; they show the number of each atomthey show the number of each atom

Helpful to remember...Helpful to remember...

5. A 5. A Roman numeralRoman numeral after the name of after the name of a cation shows the a cation shows the ionic chargeionic charge of of the cationthe cation

Use the Use the handout sheetshandout sheets provided provided by your teacher!by your teacher!

Summary of Naming and Summary of Naming and Formula WritingFormula Writing

For naming, follow the flowchart- Fig. For naming, follow the flowchart- Fig. 6.21, page 1616.21, page 161

For writing formulas, follow the For writing formulas, follow the flowchart from Fig. 6.23, p. 162flowchart from Fig. 6.23, p. 162

Documents

Chapter 6 Chemical Names and Formulas. Section 6.1 Introduction to Chemical Bonding OBJECTIVES: OBJECTIVES: Distinguish between ionic and molecular compounds