Chapter 5 Types of Chapter 5 Types of CompoundsCompounds

5.1 Ionic Compounds5.1 Ionic Compounds

5.2 Molecular Substances5.2 Molecular Substances

5.1 Ionic Compounds - 5.1 Ionic Compounds - ObjectivesObjectives

Apply ionic charge to writing Apply ionic charge to writing formulas for ionic compoundsformulas for ionic compounds

Apply formulas to name ionic Apply formulas to name ionic compoundscompounds

Interpret the information in a Interpret the information in a chemical formulachemical formula

Formula and Names of Ionic Formula and Names of Ionic CompoundsCompounds

Ionic compounds are composed of ions Ionic compounds are composed of ions bound by ionic bonds usually a metal bound by ionic bonds usually a metal and a nonmetaland a nonmetal

Ionic bonds are strong attractive forcesIonic bonds are strong attractive forces Ionic compounds are usually solids at Ionic compounds are usually solids at

room temperatureroom temperature Many are crystallineMany are crystalline Difficult to melt Difficult to melt high melting points high melting points When melted or in solutions they When melted or in solutions they

conduct electricityconduct electricity

Binary Ionic CompoundsBinary Ionic Compounds

Binary compoundBinary compound- composed of two - composed of two elementselements

Binary ionic compoundsBinary ionic compounds- composed - composed of two different ionsof two different ions NaClNaCl KIKI CaFCaF22

IonsIons

Positively charged = cationPositively charged = cation When naming the name stays the sameWhen naming the name stays the same

Calcium ionCalcium ion Sodium ionSodium ion

Negatively charged = anionNegatively charged = anion When naming the name is changedWhen naming the name is changed Ending becomes Ending becomes –ide–ide

Chloride ionChloride ion Sulfide ionSulfide ion

Naming Binary Ionic Naming Binary Ionic CompoundsCompounds

Always write the cation first followed Always write the cation first followed by the anion.by the anion.

Make sure the anion ending is Make sure the anion ending is modified to –ide.modified to –ide. NaNa++ + Cl + Cl-- Sodium Chloride Sodium Chloride KK++ + I + I-- Potassium Iodide Potassium Iodide

Writing Binary Ionic Compound Writing Binary Ionic Compound FormulasFormulas

Compounds are always neutralCompounds are always neutral Net ionic charge must always be zeroNet ionic charge must always be zero Use subscripts to indicate when more than Use subscripts to indicate when more than

one ion of an element is presentone ion of an element is present When only one ion is present, no subscript is When only one ion is present, no subscript is

needed needed NaClNaCl

When more than one is present subscripts are When more than one is present subscripts are needneed

CaFCaF22 1 Calcium ion and 2 fluoride ions 1 Calcium ion and 2 fluoride ions

Binary Ionic CompoundsBinary Ionic Compounds

Always written in the smallest whole Always written in the smallest whole number ratio – number ratio – Formula UnitFormula Unit Example Calcium FluorideExample Calcium Fluoride

Predicting Charges on IonsPredicting Charges on Ions

Oxidation NumberOxidation Number- the charge on the - the charge on the ion ion

Metals always lose electrons when Metals always lose electrons when they form ionsthey form ions

Nonmetals always gain electrons Nonmetals always gain electrons when they form ionswhen they form ions

Periodic table can be used to predict Periodic table can be used to predict the oxidation number (charge of ion) the oxidation number (charge of ion) of some elementsof some elements

Table 5.1 Ionic Charges of Table 5.1 Ionic Charges of Representative ElementsRepresentative Elements

Group Number Oxidation Number Group Number Oxidation Number ExamplesExamples

MetalsMetals

1 1+ Li1 1+ Li++, Na, Na++, , KK++

2 2+ Mg2 2+ Mg2+2+, , CaCa2+2+

13 3+ B13 3+ B3+3+, Al, Al3+3+

NonmetalsNonmetals

15 3- N15 3- N3-3-, P, P3-3-

16 2- O16 2- O2-2-, S, S2-2-

17 1- F17 1- F--, Cl, Cl--, Br, Br--, I, I--

Let’s Try It!Let’s Try It!

Write the formula for an ionic Write the formula for an ionic compound containing sodium and compound containing sodium and sulfur.sulfur.

What is the name of the compound?What is the name of the compound?

Write a formula for each of the Write a formula for each of the following compoundsfollowing compounds

1.1. Lithium oxideLithium oxide

2.2. Calcium bromideCalcium bromide

3.3. Sodium oxideSodium oxide

4.4. Aluminum sulfideAluminum sulfide

Write the formula & name for Write the formula & name for the compound formed from the compound formed from

each of the following pairs of each of the following pairs of elements.elements.

1.1. Barium and oxygenBarium and oxygen

2.2. Strontium and iodineStrontium and iodine

3.3. Lithium and chlorineLithium and chlorine

4.4. Radium and chlorineRadium and chlorine

5.1 Ionic Compounds5.1 Ionic Compounds

Compounds Containing Compounds Containing Polyatomic IonsPolyatomic Ions

Polyatomic Ions-Polyatomic Ions-an ion that has two an ion that has two or more different elementsor more different elements

Group of atoms are covalently Group of atoms are covalently bonded together when the atoms bonded together when the atoms share electronsshare electrons

The individual atoms do not have a The individual atoms do not have a charge, but the group as a whole has charge, but the group as a whole has an overall chargean overall charge

Polyatomic IonsPolyatomic Ions

Ionic compounds may contain Ionic compounds may contain positive metal ions bonded to positive metal ions bonded to negative polyatomic ions or negative negative polyatomic ions or negative nonmetal ions bonded to positive nonmetal ions bonded to positive polyatomic ionspolyatomic ions

Writing formulas using Writing formulas using Polyatomic IonsPolyatomic Ions

Treat the polyatomic ion as one unit Treat the polyatomic ion as one unit or a single ionor a single ion

Write the cation ion first followed by Write the cation ion first followed by the anionthe anion

When more than one polyatomic ion When more than one polyatomic ion is needed to make the net charge is needed to make the net charge zero you place it in parentheses and zero you place it in parentheses and then add the subscript.then add the subscript.

Common Polyatomic IonsCommon Polyatomic Ions1- charge1- charge 2- charge2- charge 3- charge3- charge

FormulFormulaa

NameName FormulFormulaa

NameName FormulaFormula NameName

HH22POPO44--

CC22HH33OO22--

HSOHSO33--

HSOHSO44--

HCOHCO33--

NONO22--

NONO33--

CNCN--

OHOH--

MnOMnO44--

ClOClO--

ClOClO22--

ClOClO33--

ClOClO44--

Dihydrogen Dihydrogen phosphatephosphate

AcetateAcetate

Hydrogen sulfiteHydrogen sulfite

Hydrogen sulfateHydrogen sulfate

Hydrogen carbonateHydrogen carbonate

NitriteNitrite

NitrateNitrate

CyanideCyanide

HydroxideHydroxide

PermanganatePermanganate

HypochloriteHypochlorite

ChloriteChlorite

ChlorateChlorate

PerchloratePerchlorate

HPOHPO442-2-

CC22OO442-2-

SOSO332-2-

SOSO442-2-

COCO332-2-

CrOCrO442-2-

CrCr22OO772-2-

SiOSiO332-2-

Hydrogen Hydrogen phosphatephosphate

OxalateOxalate

SulfiteSulfite

SulfateSulfate

CarbonateCarbonate

ChromateChromate

DichromateDichromate

SilicateSilicate

POPO443-3-

POPO333-3-

PhosphatPhosphatee

PhosphitePhosphite

1+ charge1+ chargeFormulaFormula NameName

NHNH44++

HH33OO++

AmmoniuAmmoniumm

HydroniuHydroniumm

Naming Polyatomic IonsNaming Polyatomic Ions

Follows the same rules as naming binaryFollows the same rules as naming binary Name the cation first and then the anionName the cation first and then the anion You do not change the ending of the anion for You do not change the ending of the anion for

polyatomic ionspolyatomic ions -ite-ite indicates one less oxygen atom than indicates one less oxygen atom than -ate -ate -ate-ate indicates one more oxygen atom than indicates one more oxygen atom than –ite–ite Does not tell you the number of oxygen atoms Does not tell you the number of oxygen atoms

in the ionin the ion

Let’s Try It!Let’s Try It!

Write the formula for the Write the formula for the compounds made from each of the compounds made from each of the following ions.following ions.

1.1. Ammonium and sulfite ionsAmmonium and sulfite ions

2.2. Calcium and hydrogen phosphate ionsCalcium and hydrogen phosphate ions

3.3. Ammonium and dichromate ionsAmmonium and dichromate ions

4.4. Barium and nitrate ionsBarium and nitrate ions

Let’s Try It!Let’s Try It!

Write the formula for each of the Write the formula for each of the following compounds.following compounds.

1.1. Sodium phosphateSodium phosphate

2.2. Magnesium hydroxideMagnesium hydroxide

3.3. Ammonium phosphateAmmonium phosphate

4.4. Potassium dichromatePotassium dichromate

Compounds of Transition Compounds of Transition ElementsElements

Transition elements are groups 3 Transition elements are groups 3 through 12 in the periodic tablethrough 12 in the periodic table

Form positive ions, but they form more Form positive ions, but they form more than one type of positive ionsthan one type of positive ions Copper forms two ions one with a +1 Copper forms two ions one with a +1

charge and one with a +2 chargecharge and one with a +2 charge The way they are distinguished is with The way they are distinguished is with

roman numeral. Copper (I) and Copper (II)roman numeral. Copper (I) and Copper (II)

Names of Common Ions of Selected Transition ElementsNames of Common Ions of Selected Transition Elements

ElementElement IonIon Chemical Chemical NameName

ChromiumChromium CrCr2+2+

CrCr3+3+

CrCr6+6+

Chromium (II)Chromium (II)

Chromium (III)Chromium (III)

Chromium (VI)Chromium (VI)

CobaltCobalt CoCo2+2+

CoCo3+3+

Cobalt (II)Cobalt (II)

Cobalt (III)Cobalt (III)

CopperCopper CuCu++

CuCu2+2+

Copper (I)Copper (I)

Copper (II)Copper (II)

GoldGold AuAu++

AuAu3+3+

Gold (I)Gold (I)

Gold (III)Gold (III)

IronIron FeFe2+2+

FeFe3+3+

Iron (II)Iron (II)

Iron (III)Iron (III)

ManganeseManganese MnMn2+2+

MnMn3+3+

MnMn7+7+

Manganese (II)Manganese (II)

Manganese (III)Manganese (III)

Manganese (VII)Manganese (VII)

MercuryMercury HgHg++

HgHg2+2+

Mercury (I)Mercury (I)

Mercury (II)Mercury (II)

NickelNickel NiNi2+2+

NiNi3+3+

NiNi4+4+

Nickel (II)Nickel (II)

Nickel (III)Nickel (III)

Nickel (IV)Nickel (IV)

Let’s Try It!Let’s Try It!

Write the formula for the Write the formula for the compounds made from each of the compounds made from each of the following pairs of ions.following pairs of ions.

1.1. Copper (I) and sulfiteCopper (I) and sulfite

2.2. Tin (IV) and fluorideTin (IV) and fluoride

3.3. Gold (III) and cyanideGold (III) and cyanide

4.4. Lead (II) and SulfideLead (II) and Sulfide

Let’s Try It!Let’s Try It!

Write the names of the following Write the names of the following compounds.compounds.

1.1. Pb(NOPb(NO33))22

2.2. MnMn22OO33

3.3. Ni(CNi(C22HH33OO22))22

4.4. HgFHgF22

HydratesHydrates

Many ionic compounds are prepared by Many ionic compounds are prepared by crystallization from a water solution, and crystallization from a water solution, and water molecules become a part of the water molecules become a part of the crystal.crystal.

Hydrates-Hydrates- a compound in which there is a a compound in which there is a specific ratio of water to ionic compound.specific ratio of water to ionic compound.

In hydrate, the water molecules are In hydrate, the water molecules are chemically bonded to the ionic chemically bonded to the ionic compoundcompound

Hygroscopic Hygroscopic

Hygroscopic-Hygroscopic- a substance that absorbs water a substance that absorbs water molecules from the air to become a hydrate.molecules from the air to become a hydrate. Sodium CarbonateSodium Carbonate

Some substances are so hygroscopic that Some substances are so hygroscopic that they take up enough water from the air to they take up enough water from the air to dissolve completely and form a liquid dissolve completely and form a liquid solution. These compounds are called solution. These compounds are called deliquescent.deliquescent. Sodium HydroxideSodium Hydroxide

Writing Formulas for Writing Formulas for HydratesHydrates

When writing a formula for a hydrate When writing a formula for a hydrate you place a dot in the formula you place a dot in the formula between the ionic compound and the between the ionic compound and the water.water. CaSOCaSO44 · 2H· 2H22OO What this means is for every one What this means is for every one

calcium sulfate there are two water calcium sulfate there are two water molecules in the hydrate.molecules in the hydrate.

Naming HydratesNaming Hydrates

You use the regular name for the You use the regular name for the compound followed by the word compound followed by the word hydratehydrate, , to which a prefix is added.to which a prefix is added. 1 = mono-1 = mono- 2 = di-2 = di- 3 = tri- 3 = tri- 4 = tetra-4 = tetra-

Exp.: CaSOExp.: CaSO44 · 2H· 2H22O O Calcium sulfate Calcium sulfate dihydratedihydrate

AnhydrousAnhydrous

Anhydrous – Anhydrous – a compound in which all the a compound in which all the water has been removed, usually by water has been removed, usually by heatingheating

In some cases the anhydrous compound In some cases the anhydrous compound may be a different color than the hydrate.may be a different color than the hydrate. Copper (II) sulfate pentahydrate is blue Copper (II) sulfate pentahydrate is blue

compound when it is heated to remove the compound when it is heated to remove the water and become anhydrous it turns white, water and become anhydrous it turns white, this compound is Copper (II) sulfate anhydrousthis compound is Copper (II) sulfate anhydrous

HomeworkHomework

P. 184-185 #1-5, 7, 8 P. 184-185 #1-5, 7, 8