Post on 27-Mar-2015
I II III IV
Ch. 6 & 7 - Chemical Bonding
I. Introduction toBonding
(p. 161 – 163)
A. Vocabulary
Chemical Bond
attractive force between atoms or ions that binds them together as a unit
bonds form in order to…decrease potential energy (PE)increase stability
A. Vocabulary
CHEMICAL FORMULA
MolecularFormula
FormulaUnit
IONIC COVALENT
COCO22NaClNaCl
A. Vocabulary
COMPOUND
TernaryCompound
BinaryCompound
2 elementsmore than 2
elements
NaNONaNO33NaClNaCl
A. Vocabulary
ION
PolyatomicIon
MonatomicIon
1 atom 2 or more atoms
NONO33--NaNa++
IONIC COVALENTBond Formation
Type of Structure
Solubility in Water
Electrical Conductivity
OtherProperties
e- are transferred from metal to nonmetal
high
yes (solution or liquid)
yes
e- are shared between two nonmetals
low
no
usually not
MeltingPoint
crystal lattice true molecules
B. Types of Bonds
Physical State solid liquid or gas
odorous
“electron sea”
METALLICBond Formation
Type of Structure
Solubility in Water
Electrical Conductivity
OtherProperties
MeltingPoint
B. Types of Bonds
Physical State
e- are delocalized among metal atoms
very high
yes (any form)
no
malleable, ductile, lustrous
solid
C. Bond Polarity
Most bonds are a blend of ionic and covalent characteristics
Difference in electronegativity determines bond type
C. Bond Polarity
Electronegativity – Remember this? Attraction an atom has for a shared pair
of electrons. higher e-neg atom -
lower e-neg atom +
C. Bond Polarity
Electronegativity Trend (p. 151) Increases up and to the right.
Nonpolar Covalent Bond e- are shared equally symmetrical e- density usually identical atoms
C. Bond Polarity
+ -
C. Bond Polarity
Polar Covalent Bond e- are shared unequally asymmetrical e- density results in partial charges (dipole)
Nonpolar
Polar
Ionic
View Bonding Animations.
C. Bond Polarity
C. Bond Polarity
Examples:
Cl2
HCl
NaCl
3.0-3.0=0.0Nonpolar
3.0-2.1=0.9Polar
3.0-0.9=2.1Ionic