ANSWERS

1)antimony tribromide _______SbBr3___

 

2)hexaboron silicide ____________B6S____________

 

3)chlorine dioxide ____________ClO2__________

 

4) iodic acid ________________HIO3______________

 

5) iodine pentafluoride ________IF5_______________

 

6)dinitrogen trioxide ____________N2O3______________

 

7)ammonia ________________NH3_________

 

8)hypophosphorous acid ______________H3PO2_____________

 

ANSWERS

9)P4S5 ___tertaphosphorous pentasilicide____ 10) O2 ___oxygen__________ 11) HNO4 _____pernitric acid______ 12) Si2Br6 _____disilicon hexabromide____________ 13) SCl4 _____silicon tertachloride__________ 14) CH4 _____carbon tetrahydride___(methane)______ 15) H2SO3 ______sulfurous acid__________ 16) NF3 ________nitrogen trifluoride_____________

9.3 Molecular Structure

Molecular Structures

Ball and Stick model

StickModel

Space FillingModel

Structural Formula

O

H O S O H

O

H2SO4 NH3

H N H H

WaterH O H

CH4 H

H C H

H

Lewis Structure

O

H O S O H

O

H2SO4 NH3

Water CH4 H

H C H

H

OH H

NH

H

H

General Lewis Structure Rules

1) Predict Atom locationsa) H is always terminalb) Lowest Electronegativity

is central atom

H C2.55

O3.44

C4H8O2

General Lewis Structure Rules

1) Predict Atom locationsa) H is always terminalb) Lowest Electronegativity is

central atom

2) Find total number of bonding e-

H –

C –

O – 36

1 x 8 = 8

4 x 4 = 16

6 x 2 = 12

C4H8O2

General Lewis Structure Rules

1) Predict Atom locationsa) H is always terminalb) Lowest Electronegativity

is central atom

2) Find total number of bonding e-

3) Find number of pairs

36/2=18

C4H8O2

General Lewis Structure Rules

1) Predict Atom locationsa) H is always terminalb) Lowest Electronegativity

is central atom

2) Find total number of bonding e-

3) Find number of pairs4) Place one bond

between central atom and each outer atom

C4H8O2 18

C

C

C

C

H

H

H

HH

H

H

H

O

O

-13

5

General Lewis Structure Rules

1) Predict Atom locationsa) H is always terminalb) Lowest Electronegativity is

central atom

2) Find total number of bonding e-

3) Find number of pairs4) Place one bond between

central atom and each outer atom

5) Place remaining e- pairs around outer atoms

C4H8O2 18

C

C

C

C

H

H

H

HH

H

H

H

O

O

-13

5

General Lewis Structure Rules

1) Predict Atom locationsa) H is always terminalb) Lowest Electronegativity is central

atom

2) Find total number of bonding e- 3) Find number of pairs4) Place one bond between

central atom and each outer atom

5) Place remaining e- pairs around outer atoms

6) Form double (triple) bonds to give central atom an octet

C4H8O2

C

C

C

C

H

H

H

HH

H

H

H

O

O

Polyatomic Ions

CationsNH4

+

AnionsSulfate

H – 1x4=4N – 5x1=5 9

(+) = -1 8

8

S – 6x1 = 6O – 6x4 = 24

30

(2-) = 232

26

Polyatomic Ions

CationsNH4

+

AnionsSulfate8 26

N H

H

H

H

+

S O

O

O

O

2-

Get to WorkDraw Structural Formulas

C2H6

N2

CO2

O3

C C

H

H

H

H

H

H

N N

O C O

Resonance

O3

O

O O

O

O O

Resonance Structures

A molecule has resonance when you can draw multiple Lewis Structures

NO3-

N

O O

O-

Resonance Structures

A molecule has resonance when you can draw multiple Lewis Structures

NO3-

N

O O

O-

Second Chance

O3

SO2

O

O O

S

O O

Exceptions

I. Odd number of e-

II. Fewer than 8 e-

III. Expanded Octet

NO2

BH3

SF6

O N O

H B H

H

SF

FF

F

F

F

Exceptions

Fewer than 8 e-

H B

H

H

N

H

H

H

Coordinate Covalent Bond1 atom donates both e- to share