Compounds & Compounds & MoleculesMoleculesCompounds & Compounds & MoleculesMolecules

NaCl, saltNaCl, salt

Buckyball, CBuckyball, C6060

Compounds & Compounds & MoleculesMoleculesCompounds & Compounds & MoleculesMolecules

•COMPOUNDSCOMPOUNDS are a combination of 2 are a combination of 2

or more elements in definite ratios by mass. or more elements in definite ratios by mass.

• The character of each element is lost when The character of each element is lost when

forming a compound.forming a compound.

•MOLECULESMOLECULES are the smallest unit of a are the smallest unit of a

compound that retains the characteristics of compound that retains the characteristics of

the compound.the compound.

ELEMENTS THAT EXIST AS ELEMENTS THAT EXIST AS DIATOMICDIATOMIC MOLECULES MOLECULES

ELEMENTS THAT EXIST AS ELEMENTS THAT EXIST AS DIATOMICDIATOMIC MOLECULES MOLECULES

ELEMENTS ELEMENTS THAT EXIST THAT EXIST

AS AS MOLECULESMOLECULES

ELEMENTS ELEMENTS THAT EXIST THAT EXIST

AS AS MOLECULESMOLECULES

Allotropes of CAllotropes of CAllotropes of CAllotropes of C

ELEMENTS THAT EXIST AS ELEMENTS THAT EXIST AS POLYATOMICPOLYATOMIC MOLECULES MOLECULESELEMENTS THAT EXIST AS ELEMENTS THAT EXIST AS POLYATOMICPOLYATOMIC MOLECULES MOLECULES

White P4 and polymeric red phosphorus

S8 sulfur molecules

Molecular CompoundsMolecular CompoundsCompounds without IonsCompounds without Ions

CH4 methane

CO2 Carbon dioxide

BCl3 boron trichloride

MOLECULAR FORMULASMOLECULAR FORMULASMOLECULAR FORMULASMOLECULAR FORMULAS

• Formula for glycine is Formula for glycine is CC22HH55NONO22

• In one molecule there areIn one molecule there are

–2 C atoms2 C atoms

–5 H atoms5 H atoms

–1 N atom1 N atom

–2 O atoms2 O atoms

STRUCTUAL STRUCTUAL FORMULASFORMULASSTRUCTUAL STRUCTUAL FORMULASFORMULAS

• Can also write glycine formula as

–H2NCH2COOHto show atom ordering

• or in the form of a structuralstructural formula formula

C

H

H C

H

H

O

O HN

MOLECULAR MOLECULAR MODELINGMODELING

MOLECULAR MOLECULAR MODELINGMODELING

C

H

H C

H

H

O

O HN

Ball & stickBall & stick Space-fillingSpace-filling

Drawing of glycineDrawing of glycine

Naming Elements & CompoundsNaming Elements & CompoundsChapter 2 & 3: Chemical Equations HandbookChapter 2 & 3: Chemical Equations Handbook

BCl3 boron trichloride

CO2 Carbon dioxide

molecules are formed from two or more nonmetals.

Ionic compounds

have a cation and anion: generally

involve a metal and nonmetal,

NaCl

ammonium ammonium chloride, chloride,

NHNH4ClCl

IONS AND IONIC COMPOUNDSIONS AND IONIC COMPOUNDS

• IONSIONS are atoms or groups of atoms with a positive are atoms or groups of atoms with a positive

or negative charge. or negative charge.

• Taking awayTaking away an electron from an atom gives a an electron from an atom gives a

CATIONCATION with a with a positive chargepositive charge

• AddingAdding an electron to an atom gives an an electron to an atom gives an ANIONANION

with a with a negative chargenegative charge..

Forming Cations & Forming Cations & AnionsAnions

Forming Cations & Forming Cations & AnionsAnions

A A CATIONCATION forms forms when an when an atom atom losesloses one or one or more electrons.more electrons.

An An ANIONANION forms forms when an when an atom atom gainsgains one or one or more electronsmore electrons

Mg --> Mg2+ + 2 e- F + e- --> F-

CATIONCATION + + ANIONANION ---> --->

COMPOUNDCOMPOUND

CATIONCATION + + ANIONANION ---> --->

COMPOUNDCOMPOUND

Are NEUTRAL. Are NEUTRAL. Compounds haveCompounds have

EQUAL number of EQUAL number of ++ and and -- charges. charges.

Are NEUTRAL. Are NEUTRAL. Compounds haveCompounds have

EQUAL number of EQUAL number of ++ and and -- charges. charges.

COMPOUNDCOMPOUNDS FORMED S FORMED FROM IONSFROM IONS

COMPOUNDCOMPOUNDS FORMED S FORMED FROM IONSFROM IONS

NaNa++ + Cl + Cl- - --> NaCl--> NaCl

IONIC COMPOUNDSIONIC COMPOUNDSIONIC COMPOUNDSIONIC COMPOUNDS

NH4+

Cl-

ammonium chloride, NHammonium chloride, NH44ClCl

Properties of Ionic Properties of Ionic CompoundsCompounds

Forming NaCl from Na and ClForming NaCl from Na and Cl22

Properties of Ionic Properties of Ionic CompoundsCompounds

Forming NaCl from Na and ClForming NaCl from Na and Cl22

• A metal atom can A metal atom can transfer an transfer an electron to a electron to a nonmetal.nonmetal.

• The resulting The resulting cation and anion cation and anion are attracted to are attracted to each other by each other by

electrostatelectrostatic forcesic forces..

Electrostatic ForcesElectrostatic Forces

The oppositely charged ions in ionic compounds are The oppositely charged ions in ionic compounds are attracted to one another by attracted to one another by ELECTROSTATIC ELECTROSTATIC FORCESFORCES..

These forces are governed by These forces are governed by COULOMB’S COULOMB’S LAWLAW..

Electrostatic ForcesElectrostatic Forces

COULOMB’S LAWCOULOMB’S LAW

Force of attraction = (charge on +)(charge on -)

(distance between ions)2

DirectDirect relationship between relationship between chargecharge and and forceforce: : charges increase, the force increases.charges increase, the force increases.

InverseInverse relationship between relationship between distancedistance between between ions and ions and forceforce::

increase distance, decrease force.increase distance, decrease force.

Importance of Coulomb’s Importance of Coulomb’s LawLaw

NaCl, NaNaCl, Na++ and Cl and Cl--,,m.p. 804 m.p. 804 ooCC

MgO, MgMgO, Mg2+2+ and O and O2-2-

m.p. 2800 m.p. 2800 ooCC

PREDICTING ION CHARGESPREDICTING ION CHARGESPREDICTING ION CHARGESPREDICTING ION CHARGES

In generalIn general

• metalsmetals (Mg) (Mg) lose electrons lose electrons ---> ---> cationscations

• nonmetalsnonmetals (F) (F) gain electronsgain electrons ---> ---> anionsanions

METALSMETALSM ---> n e- + MM ---> n e- + Mn+n+

where n = periodic groupwhere n = periodic groupNaNa++ sodium ionsodium ionMgMg2+2+ magnesium ionmagnesium ionAlAl3+3+ aluminum ionaluminum ionTransition metals --> MTransition metals --> M2+2+ or M or M3+3+

are commonare commonFeFe2+2+ iron(II) ioniron(II) ionFeFe3+3+ iron(III) ioniron(III) ion

NONMETALSNONMETALSNONMETALSNONMETALS

NONMETAL + n e- ------> XNONMETAL + n e- ------> Xn-n-

where n = 8 - Group no.where n = 8 - Group no.

CC4-4-,carbide,carbide NN3-3-, nitride, nitride OO2-2-, oxide, oxide

SS2-2-, sulfide, sulfide

FF--, fluoride, fluoride

ClCl--, chloride, chloride

Group 7AGroup 6AGroup 4A Group 5A

BrBr--, bromide, bromide

II--, iodide, iodide

Charges on Common Charges on Common IonsIons

Charges on Common Charges on Common IonsIons

+3

-4 -1-2-3+1

+2

By losing or gaining e-, atom has same By losing or gaining e-, atom has same number of e-’s as nearest Group 8A atom.number of e-’s as nearest Group 8A atom.

Predicting Charges on Monatomic IonsPredicting Charges on Monatomic Ions

Binary Ionic Binary Ionic CompoundsCompoundsBinary Ionic Binary Ionic CompoundsCompounds

MnMn2+2+ + O + O2-2- ----> MnO ----> MnO

manganese (II)manganese (II) oxideoxide

AlAl3+3+ + S + S2-2- ----> Al ----> Al22SS33

aluminum sulfidealuminum sulfide

SnSn4+4+ + Cl + Cl-- ----> SnCl ----> SnCl44

Tin (IV) chloride orTin (IV) chloride or

Stannic chlorideStannic chloride calcium fluoridecalcium fluoride

CaCa2+2+ + 2 F + 2 F-- ---> --->

CaFCaF22

Practice Name & Formulas Ultimate Equation Handbook

Only the binary compounds

• Exercise 2-1 pg. 10

• Exercise 3-2 pg 17

Homework:

Worksheets pgs 23-28

POLYATOMIC POLYATOMIC IONSIONS

POLYATOMIC POLYATOMIC IONSIONS

Groups of atoms with a charge.Groups of atoms with a charge.

MEMORIZEMEMORIZE the names and formulas in the names and formulas in

Table 3.1, page 89.Table 3.1, page 89.

Polyatomic IonsPolyatomic IonsPolyatomic IonsPolyatomic Ions

NHNH44++

ammonium ionammonium ion

One of the few common One of the few common polyatomic polyatomic cationscations

Polyatomic IonsPolyatomic IonsPolyatomic IonsPolyatomic Ions

HNOHNO33

nitric acidnitric acid

NONO33--

nitrate ionnitrate ion

Polyatomic Polyatomic IonsIonsPolyatomic Polyatomic IonsIonsCOCO33

2-2-

carbonate ioncarbonate ion

HCOHCO33--

bicarbonate ionbicarbonate ion

hydrogen carbonatehydrogen carbonate

POPO443-3-

phosphate ionphosphate ion

CHCH33COCO22--

acetate ionacetate ion

Polyatomic Polyatomic IonsIons

Polyatomic Polyatomic IonsIons

SOSO442-2-

sulfate ionsulfate ion

SOSO332-2-

sulfite ionsulfite ion

Polyatomic Polyatomic IonsIons

Polyatomic Polyatomic IonsIons

NONO33--

nitrate ionnitrate ion

NONO22--

nitrite ionnitrite ion

Polyatomic Polyatomic IonsIons

Polyatomic Polyatomic IonsIons

“ates”

Worksheet pg #22

Practice Name & Formulas Ultimate Equation Handbook

Add the polyatomic compounds• Exercise 2-1 pg. 10• Exercise 3-2 pg 17• Exercise 4-1 pg 20• Exercise 4-3 pg 21

Homework:Worksheets pgs 23-28 –poly

Pgs 29-33

Molecular & Ionic Molecular & Ionic CompoundsCompounds

HemeHeme NaClNaCl