NOTES: CHEMICAL BONDING - Livingston



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!

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 points

electrons 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

COVALENT COMPOUNDS: POLAR VS. NON-POLAR

nonpolar covalent compound:

dispersion force:

polar covalent compound:

dipole force:

Properties:

NONPOLAR COVALENT:

POLAR COVALENT

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 atom

3. 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 1x

O unless an ion, bonds 2x

N usually bonds 3x

C always in the center, always bonds 4x

|H2 | |PH3 | |

| | | | |

| | | | |

| | | | |

| | | | |

|H2O | |CH4 | |

| | | | |

| | | | |

| | | | |

| | | | |

|NH3 | |O2 | |

| | | | |

| | | | |

| | | | |

| | | | |

|N2 | |CH2O | |

| | | | |

| | | | |

| | | | |

| | | | |

|CO2 | |HCN | |

| | | | |

| | | | |

| | | | |

| | | | |

|NH4+1 | |C2F2 | |

| | | | |

| | | | |

| | | | |

| | | | |

|SPECIAL EXAMPLES: COORDIANTE COVALENT BONDING |

|O3 | |SO2 | |

| | | | |

| | | | |

| | | | |

| | | | |

|SO32- | |NO3-1 | |

| | | | |

| | | | |

| | | | |

| | | | |

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

|EXAMPLE |LEWIS |XY |3D DIAGRAM |ANGLE/ |

| |DIAGRAM |NOTATION | |GEOMETRY |

| | | |[pic] |Linear |

|HCl |[pic] |XY | |180º |

| | | | | |

| | |diatomic molecule | | |

| |[pic] | | |Linear |

|CO2 | |XY2 No lone pair! |[pic] |180º |

| | | | | |

| | |2 atoms attached to central atom | | |

| |[pic] | |[pic] |Trigonal Planar |

| | |XY3 No lone pair! | |120º |

|BF3 | | | | |

| | |3 atoms attached to central atom | | |

| |[pic] | |[pic] | |

| | |XY4 No lone pair! | |Tetrahedral |

|CH4 | | | |109.5º |

| | |4 atoms attached to central atom | | |

| |[pic] | |[pic] |Pyramidal |

| | |XY3E (E=electron pair) | |(Trigonal Pyramidal) |

|NH3 | | | | 10 minutes* |did not dissolve |none | |

|5. |Crystalline solid |(*would not melt in our | | | |

| | |lab) | | | |

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. PO33-

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

HOMEWORK: LEWIS DIAGRAMS

| |SCRATCH WORK |STRUCTURAL, LEWIS OR VSEPR |NAME OF |BOND |IS THE MOLECULE POLAR? |MP/BP |DISSOLVES IN? |

| | |DIAGRAM |SHAPE |ANGLE |(YES OR NO?) | | |

| | | | | |(dispersion or dipole?) | | |

| | | | | | | | |

| | | | | | | | |

|H2Se | | | | | | | |

| | | | | | | | |

| | | | | | | | |

|AsF3 | | | | | | | |

| | | | | | | | |

|BF3 | | | | | | | |

| | | | | | | | |

|**B is an | | | | | | | |

|exception, it | | | | | | | |

|only gets 6 | | | | | | | |

| | | | | | | | |

|N2 | | | | | | | |

| | | | | | | | |

| | | | | | | | |

| | | | | | | | |

|SiCl4 | | | | | | | |

| | | | | | | | |

| | | | | | | | |

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

2. Complete the chart below:

Formula |Lewis Structure

|Molecular Shape

(diagram)

|Name of Shape

|Bond Angle |Polar?

Dipole or Dispersion? |MP/BP? |Dissolves in? |Conducts? | |

1. PBr3 | | | | | | | | | |

2. C2Cl2 | | | | | | | | | |

3. SiCl4 | | | | | | | | | |

4. O2 | | | | | | | | | |

5. HClO3 | | | | | | | | | |

6. PO43- | | | | | | | | | |

3. PRACTICE WITH COORDINATE COVALENT EXAMPLES:

Formula |Lewis Structure

|Molecular Shape

(diagram)

|Name of Shape

|Bond Angle |Polar?

Dipole or Dispersion? |MP/BP? |Dissolves in? |Conducts? | |

1. NO3-1

| | | | | | | | | |

2. SO2

| | | | | | | | | |

3. SO3-2

| | | | | | | | | |

-----------------------

Free-floating Valence electrons

Positive metal ions in fixed positions

[pic] [pic]

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

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download