TYPES OF BONDING AND PROPERTIES

IONIC BONDING Metal + monoatomic ion Metal + polyatomic ion Positive ion + negative ion

Draw Lewis dot structures for: Ionic bonds-intramolecular forces

Compounds Before After

Calcium chloride

Aluminum Fluoride

PROPERTIES OF IONIC COMPOUNDS

SOLID at room temperature

Has a “Crystal” Structure

High melting & boiling points

Does NOT conduct electricity (solid state)

CAN conduct electricity when dissolved in water & molten

METALLIC BONDING: Metals only! 1

Positive metal ions in fixed positions

Metallic bonds: the forces of attraction between the free-floating valence electrons and the positively charged metal ions.

PROPERTIES OF METALS: delocalized electrons - “sea” of mobile electrons *Metallic bonds-intramolecular

Solid at room temperature (EXCEPT MERCURY)

Has a “Crystal” Structure

Shiny, malleable, ductile

Medium-high melting & boiling pointselectrons can flow freely

Good conductors of electric current & heat

NETWORK COVALENT BONDING:

Network covalent substances: atoms are covalently bonded with each other WITHOUT ever forming separate molecules. Instead, the bonds extend throughout the entire solid like one giant molecule. THESE ARE THE STRONGEST COMPOUNDS!!!!

PROPERTIES OF NETWORK COVALENT BONDING:

Solid at room temperature

Has a “Crystal” Structure

VERY high boiling and melting points

Non-conducting

2

Free-floating Valence electrons

COVALENT COMPOUNDS: POLAR VS. NON-POLAR

nonpolar covalent compound:

dispersion force:

polar covalent compound:

dipole force:

Properties:NONPOLAR COVALENT:

POLAR COVALENT

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NON-POLAR POLAR(dispersion forces ONLY exist between molecules) (dispersion & dipole forces exist between molecules)

TRY: Label the substances below as: metallic, ionic, network covalent, molecular (non-polar) or molecular (polar).

a. dissolves in water, does not conduct electricity as a solid, but does when dissolved in water

b. dissolves in acetone, low boiling point

c. shiny, conducts electricity as a solid

d. gas at room temperature

e. NH3

f. NaBr

g. CO2

COVALENT BONDING:

non-metals ONLY!

HINTS FOR DRAWING DOT DIAGRAMS FOR MOLECULAR COMPOUNDS

1. choose a central atom (the most needy. NEVER HYDROGEN OR A HALOGEN)2. Arrange other atoms around central atom3. Determine the number of valence electrons for each atom based on the periodic table (draw the

correct number of “dots” around each atom)4. Pair electrons so that each atom follows the octet rule (or duet rule for Hydrogen, 6 for Boron)5. Use double and triple bonds if necessary.

HINTS: H, halogens never in center, always bond 1xO unless an ion, bonds 2xN usually bonds 3xC always in the center, always bonds 4x

H2 PH3

H2O CH4

NH3 O2

N2 CH2O

4

CO2 HCN

NH4+1 C2F2

SPECIAL EXAMPLES: COORDIANTE COVALENT BONDING

O3 SO2

SO32- NO3

-1

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VSEPR THEORY – Place electrons as far away from each other as possible to minimize repulsion

EXAMPLE LEWISDIAGRAM

XYNOTATION

3D DIAGRAM ANGLE/GEOMETRY

HCl XY

diatomic molecule

Linear180º

CO2 XY2 No lone pair!

2 atoms attached to central atom

Linear180º

BF3

XY3 No lone pair!

3 atoms attached to central atom

Trigonal Planar120º

CH4

XY4 No lone pair!

4 atoms attached to central atom

Tetrahedral109.5º

NH3

XY3E (E=electron pair)

3 atoms attached to central atom - 1 lone pair!

Pyramidal(Trigonal Pyramidal)<109.5º

H2OXY2E2 2 lone pairs!

2 atoms attached to central atom

Bent or Angular<<109.5º

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VSEPR DIAGRAMS AND GEOMETRY

1. Complete the chart below. SCRATCH WORK STRUCTURAL,

LEWIS OR VSEPR DIAGRAM

NAME OFSHAPE

BONDANGLE

IS THE MOLECULE

POLAR?(YES OR NO?)

(dispersion or dipole?)

MP/BP? DISSOLVES IN?

Cl2

O2

HBr

CH2S

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DIAGRAM(scratch work)

STRUCTURAL, LEWIS OR VSEPR DIAGRAM

NAME OFSHAPE

BONDANGLE

IS THE MOLECULE

POLAR?(YES OR NO?)

(dispersion or dipole?)

MP/BP DISSOLVES IN?

CF4

PH3

H2S

CS2

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DIAGRAM(scratch work)

STRUCTURAL, LEWIS OR VSEPR DIAGRAM

NAME OFSHAPE

BONDANGLE

IS THE MOLECULE

POLAR?(YES OR NO?)

(dispersion or dipole?)

MP/BP DISSOLVES IN?

CF2Cl2

PF3

OH-1

CO3-2

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HOMEWORK: SUMMARY CHART FOR BOND TYPE AND PROPERTIES

TYPE EXAMPLES DESCRIPTION MELTING & BOILING POINT

STATE AT ROOM TEMPERATURE

DISSOLVES IN?

CONDUCT ELECTRICITY?

ionic

metallic

network covalent

covalent(polar)

covalent (non-polar)

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HOMEWORK: INTERMOLECULAR FORCES

1. Label the substances below as: metallic, ionic, network covalent, molecular (nonpolar (dispersion)), molecular (polar (dipole)) or molecular (hydrogen bonding)

a. melts at 800°C, conducts electricity as a solid, does not dissolve in water __________________

b. strong odor, dissolves in gasoline, melts easily when heated __________________

c. crystalline solid, dissolves in water, solution conducts electricity __________________

d. crystalline solid, does not dissolve in water or acetone, very high melting point _______________

e. K2SO4 __________________

f. CH4 __________________

g. H2O __________________

2. Fill in the missing boxes in the chart below. The types of solid used are: Molecular (nonpolar), Molecular (polar); Ionic, Network Covalent, Metallic

Appearance Time to Melt? Dissolves in?(water, alcohol, acetone)

Conductivity? Type?

1 crystalline solid

> 10 minutes*(*would not melt in our lab)

water

2 Shiny solid > 10 minutes*(*would not melt in our lab)

As solid; liquid not tested

3. crystalline solid

4 minutes water, alcohol

4.flaky solid 30 seconds none

5. Crystalline solid

> 10 minutes*(*would not melt in our lab)

did not dissolve none

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HOMEWORK: DRAWING LEWIS

Draw each molecule below with the correct bonding. Follow the steps below:

1. Position atoms as symmetrically as possible. Put the most needy atom in the center.2. Count to make sure all atoms are up to 8 electrons, except hydrogen (2) or boron (6).

a. H2O2 b. HOBr c. H2CS

d. HCP e.. ClO31- f. PO3

3-

g. NO2-1 h. CS2 i. BF3

COORDINATE COVALENT EXAMPLES:

1. As above, place the most “needy” atom in the middle. 2. Move electrons if necessary. Do not allow the central atom to have more than 8 electrons. Instead,

“give” the electrons to another atom or atoms that need them!

a. O3

b. SO2 c. SO3

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HOMEWORK: LEWIS DIAGRAMSSCRATCH WORK STRUCTURAL,

LEWIS OR VSEPR DIAGRAM

NAME OFSHAPE

BONDANGLE

IS THE MOLECULE

POLAR?(YES OR NO?)

(dispersion or dipole?)

MP/BP DISSOLVES IN?

H2Se

AsF3

BF3

**B is an exception, it only gets 6

N2

SiCl4

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Bonding Review

Part #1: Fill in the blanks.Directions: Place the correct word or phrase in each blank.

1. All elements follow the ___________________ rule, except for __________________

and _____________________ .

2. If an element fulfills either of the two rules mentioned in question #1, then that

element has the same ______________________ as one of the ___________________________.

3. An ionic bond involves a ______________________ of electrons to the ______________

electronegative element. A covalent bond involves ___________________ of electrons.

Metallic bonding involves ______________________________________________________________, and

network covalent bonding involves __________________________________________________.

4. Lewis Dot Diagrams use dots to represent the ___________________ electrons and the chemical

symbol to represent the ______________________ electrons.

5. A _______________________ involves the sharing of two pairs of electrons and a

________________________ involves a sharing of three pairs of electrons.

Part #2: Lewis Structures 1. Draw correct Lewis Structures for the following atoms.

a. N b. I

2. Draw correct Lewis Structures for the following ionic compounds.

a. KCl b. AlF3

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3. Complete the chart below:Formula Lewis Structure Molecular Shape

(diagram)Name of Shape

Bond Angl

e

Polar?Dipole or

Dispersion?

MP/BP? Dissolves in?

Conducts?

1. PBr3

2. C2Cl2

3. SiCl4

4. O2

5. HClO3

6. PO43-

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4. PRACTICE WITH COORDINATE COVALENT EXAMPLES:

Formula Lewis Structure Molecular Shape(diagram)

Name of Shape

Bond Angl

e

Polar?Dipole or

Dispersion?

MP/BP? Dissolves in?

Conducts?

1. NO3-1

2. SO2

3. SO3-2

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