I II III IV

Chemical Bonding

Covalent Bonding

IONIC COVALENTBond Formation

Type of Structure

Solubility in Water

Electrical ConductivityOtherProperties

e- are transferred from metal to nonmetal

high

yes (solution or liquid)

yes

e- are shared between two nonmetals

low

no

usually not

MeltingPoint

crystal lattice true molecules

A. Types of Bonds

Physical State solid liquid or gas

odorous

“electron sea”

METALLICBond Formation

Type of Structure

Solubility in Water

Electrical ConductivityOtherProperties

MeltingPoint

A. Types of Bonds

Physical State

e- are delocalized among metal atoms

very high

yes (any form)

no

malleable, ductile, lustrous

solid

B. Bond PolarityMost bonds are

a blend of ionic and covalent characteristics.

Difference in electronegativity determines bond type.

B. Bond PolarityElectronegativity

Attraction an atom has for a shared pair of electrons.

higher e-neg atom -

lower e-neg atom +

B. Bond PolarityElectronegativity Trend

Increases up and to the right.

Nonpolar Covalent Bond e- are shared equally symmetrical e- density usually identical atoms Electronegativity difference range

0.00 – 0.4

B. Bond Polarity

+ -

B. Bond PolarityPolar Covalent Bond

e- are shared unequally asymmetrical e- density results in partial charges (dipole) Electronegativity difference range

0.4 – 2.0

+ -

+

B. Bond PolarityNonpolar Covalent - no charges

Polar Covalent - partial charges

Nonpolar

Polar

Ionic

View Bonding Animations.

B. Bond Polarity

B. Bond Polarity

Examples:Cl2

HCl

NaCl

3.0-3.0=0.0Nonpolar

3.0-2.1=0.9Polar

3.0-0.9=2.1Ionic

Determining Type, EN0.3

1.7

5% 50%

Determining Type, EN

Ionic, Polar or Nonpolar Covalent Compounds: The difference in electronegativity between bonding atoms leads to the type of compound.

Example:O2 , O=O ENO = 3.5 EN = 0 NO , N=O ENN = 3.0, ENO = 3.5 EN = .5 CO , C= ENC = 2.5, ENO = 3.5 EN = 1.0 NaCl , Na+Cl- ENNa = 0.9, ENCl = 3.0 EN = 2.1

Nonpolar Covalent

Polar Covalent

Ionic

Polar Covalent

Sample Problem Use electronegativity differences to classify bonding between sulfur, S, and the following elements: hydrogen, H; cesium, Cs; and chlorine, Cl. In each pair, which atom will be more negative?Bonding between sulfur and

Electronegativity difference Bond

type

More-negative atom

hydrogen 2.5 – 2.1 = 0.4 Polar-covalent

sulfurcesium 2.5 – 0.7 = 1.8 Ionic sulfurchlorine 3.0 – 2.5 = 0.5 Polar-

covalentchlorine

Additional Sample Problems

Complete the following chart:Elements bonded

Electronegativity difference Bond

type

More-negative atom

a. C and H 2.5 – 2.1 = 0.4 Polar-covalent

carbonb. C and S 2.5 – 2.5 = 0 Nonpolar

covalentSame electronegativityc. O and H 3.5 – 2.1 = 1.4 Polar-

covalentoxygen

d. Na and Cl

3.0 – 0.9 = 2.1 Ionic chlorinee. Cs and S

2.5 – 0.7 = 1.8 Ionic sulfur

LecturePLUS Timberlake 17

Learning Check

Identify the type of bond between the following atoms A. K-N

1) nonpolar 2) polar 3) ionicB. N-O

1) nonpolar 2) polar 3) ionicC. Cl-Cl

1) nonpolar 2) polar 3) ionic

LecturePLUS Timberlake 18

Solution

A. K-N 3) ionic

B. N-O 2) polar

C. Cl-Cl 1) nonpolar

Covalent Bonds can have multiple bonds, so you should be familiar with the following…Single Covalent Bond- chemical bond resulting from sharing of an electron pair between two atoms.

Double Covalent Bond- chemical bond resulting from sharing of two electron pairs between two atoms.

Triple Covalent Bond -chemical bond resulting from sharing of three electron pairs between two atoms.

C. Molecular NomenclaturePrefix System (binary compounds)

1. Less e-neg atom comes first.

2. Add prefixes to indicate # of atoms. Omit mono- prefix on first element.

3. Change the ending of the second element to -ide.

PREFIXmono-di-tri-tetra-penta-hexa-hepta-octa-nona-deca-

NUMBER12345678910

C. Molecular Nomenclature

CCl4

N2O

SF6

carbon tetrachloride

dinitrogen monoxide

sulfur hexafluoride

C. Molecular Nomenclature

arsenic trichloride

dinitrogen pentoxide

tetraphosphorus decoxide

AsCl3

N2O5

P4O10

C. Molecular Nomenclature