TYPES OF BONDING AND PROPERTIES IONIC BONDING Metal + monoatomic ion Metal + polyatomic ion Positive ion + negative ion Draw Lewis dot structures for: Ionic bonds-intra molecular 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 1
Transcript
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
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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
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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
