Molecular Models Activity

ammonia

hydrogen monochloride

trichloromethane

urea

propane

butane

nitrogen triiodide (video)

carbon tetrachloride

methane

water

ethane

ethyne

dihydrogen monosulfide

carbon dioxide

supplies

Bonding and Shape of Molecules

Number of Bonds

Number of Unshared Pairs Shape Examples

2

3

4

3

2

0

0

0

1

2

Linear

Trigonal planar

Tetrahedral

Pyramidal

Bent

BeCl2

BF3

CH4, SiCl4

NH3, PCl3

H2O, H2S, SCl2

-Be-

B

C

N

:

O

:

:

CovalentStructure

Lewis Structures

1) Count up total number of valence electrons

2) Connect all atoms with single bonds

- “multiple” atoms usually on outside

- “single” atoms usually in center;

C always in center,

H always on outside.

3) Complete octets on exterior atoms (not H, though)

4) Check

- valence electrons match with Step 1

- all atoms (except H) have an octet; if not, try multiple bonds

- any extra electrons? Put on central atom

- no unpaired electrons (free radicals)

Gilbert Lewis

Carbon tetrachloride

C ClClCl

Cl

CCl4

C109.5o

Cl

ClClCl

Carbon tetrachloride – “carbon tet” had been used as dry cleaning solventbecause of its extreme non-polarity.

Tetrahedral geometry

Methane

CHH

HH

C109.5o

H

HHH

Methane –The first member of the paraffin (alkane) hydrocarbons series. a.k.a. (marsh gas, CH4).

Tetrahedral geometry

Water

....

H HOBent

geometry

SO2

(-)

(+)

Polar molecule

Ethane

CH

CHH

HHH

space-filling molecule

ball-and-stickLewis dot notation

C2H4

molecular formula

C = 1s22s22p2

Ethane

CH

CHH

HHH

space-filling molecule

ball-and-stickLewis dot notation

C2H6

molecular formula

Ethyne

CCH H CCH H

No octet

Stable octet

6 electrons = triple bond

CCH H

C2H2

CCH H

each C “feels” 6 electrons

each C “feels” 7 carbons

Ethyne – a.k.a. “acetylene”

Dihydrogen monosulfide

....

H HS

Bent

SO2

Carbon dioxide

O OC

Lineargeometry

C OOCO2

C OO

Ammonia

NH HH

N107o HH

H

..

NH3

..

HH

H

N

TrigonalPyramidalgeometry

NH HH

H

Amino Acids – Functional Groups

Amine Carboxylic AcidBase Pair

NH21- R- COOH

NH3NH21- NH4

1+

amine ammonia ammonium ion

NH

HH

:

NH

HH

H : 1+

NH

H

:

1-

:

H+ lose H+ H+

+

Hydrogen monochloride

H ClHCl

H Cl

(-)(+)

H Cl

Polar molecule

HCl(g) + H2O(l) HCl(aq)

hydrogenchloride

water hydrochloric acid

Trichloromethane

C ClClCl

H

CHCl3

C109.5o

H

ClClCl

C ClClCl

H

(-)

(+)

Polar molecule

Tetrahedral geometry

Urea

CON HH

NH H

CON HH

NH H

CO(NH2)2

NOT “di-urea”

Urea – The first organic compound to be synthesized (Wohler, 1828).

Propane

CH

CHH

CH

HHHH

C C C

HH

H

HH H H

H

C3H8

Butane

CH

CHH

CH

C HH

HHHHH - C - C - C - C - H

H H H H

H H H H

C4H10 C C C

HH

H

HH H H

HC

H

H

Nitrogen triiodide

NI II N

107o III

..

NI3

TrigonalPyramidalgeometry

Video clip:

(slow motion)

detonation of NI3

Supplies

15 black (carbon) 8 green (chlorine and iodine) 1 yellow (sulfur) 4 blue (oxygen) 4 red (nitrogen) 42 hydrogen (hydrogen) 67 bonds (bonds)

C Cl I S O N H

C ClClCl

ClCH

H HH

C OO

SH HC C HH

C ClClCl

H

H Cl

CCl4 CH4

CO2

C2H2

HClCHCl3

SH2

CH

CHH

CH

C HH

HHHHCH

CHH

CH

HHHH

NH HH

NI II

Decomposition of Nitrogen Triiodide

Decomposition of Nitrogen Triiodide

2 NI3(s) N2(g) + 3 I2(g)

NI3 I2

N2

C109.5o

H

HHH

N107o HH

H

..

O104.5o H

H

..

..

CH4, methane NH3, ammonia H2O, water

..

O

O

O

lone pairelectrons

OOO

O3, ozone

......

The VSEPR Model

O OC

Linear

The Shapes of Some Simple ABn Molecules

O OS

BentO O

S

O

Trigonalplanar

FF

F

N

Trigonalpyramidal

T-shaped Squareplanar

F FCl

F

F F

Xe

F FF

F

FP

F

F

Trigonalbipyramidal

Octahedral

FF

F

S

F

F

F

AB6

SO2

Brown, LeMay, Bursten, Chemistry The Central Science, 2000, page 305

Resources - Nomenclature

Objectives

Worksheet - binary cmpds: single charge cation - binary cmpds: single charge cation

Worksheet - ions in chemical formulas

Worksheet - ionic cmpds: polyatomic ions w multiple-charge cation - ionic cmpds: polyatomic ions w multiple-charge cation

Worksheet - ionic formulas (binary, polyatomic, transition)

Worksheet - traditional system of nomenclature

Worksheet - covalent binary cmpds: non-metal - non-metal - covalent binary cmpds: non-metal - non-metal

Worksheet - ionic cmpds: polyatomic ions - ionic cmpds: polyatomic ions

Outline ((general)

Worksheet - empirical and molecular

Worksheet - vocab (bonding) - vocab (bonding)

Activity - bonding pieces

Activity - molecular models

Activity - mole pattern

Worksheet - binary compounds

Worksheet - ions in chemical compounds

Textbook - questions

Worksheet - ionic binary cmpds: multiple charge cation - ionic binary cmpds: multiple charge cation

Worksheet - oxidation numbers and ionic cmpds - oxidation numbers and ionic cmpds

Worksheet - names and formulas of cmpds - names and formulas of cmpds

Worksheet - errors in chemical formulas and nomenclature

General Chemistry PP