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1
Single Covalent Bonds
Structural Formulas
Unshaired Pair
Double and Triple Covalent Bonds
Carbon Dioxide
2
Draw electron dot structures for each molecule.Chlorine gasBromine
H2O2PCl3 NF3
SBr2
Resonance Structures
O3
Coordinate Covalent Bonds
Shared e‐ pair comes from one of the bonding atoms
SO42‐
Polyatomic Ions
‐Function as a unit‐Held together by covalent bonds‐Net charge (+ or ‐) makes it an ion
Exceptions to the Octet
NO2
P and S can have expanded octets
BF3
Boron can be electron deficient
3
Bond Dissociation Energy‐energy needed to break 1 mole of bonds
‐high energy = strong covalent bond
C C = 347 kj/mol
C C = 657 kj/mol
C C = 908 kj/mol
Molecular Orbitals
VSEPR Theory
8.4 Polar Bonds and Molecules
Polar covalent
Nonpolar covalent
Bond Polarity
Look at difference in electronegativity of atoms involved in bond
What you need to know....
0‐0.4 = nonpolar >1.7 = ionic(But also look for M‐NM)
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Polar Molecules
(dipole)
INTERmolecular vs. INTRAmolecular Forces
INTRAmolecular‐
Ionic Bond
Covalent Bond
Metallic Bond
‐BP is good measure of IMF
weaker than ionic or covalent bonds that join the atoms in molecules
INTERmolecular Forces‐attraction between 2 or more molecules
‐IMFs govern many physical properties like BP, MP, viscosity, surface tension
What would happen if there were no IMFs?
Van der Waals Forces
Dipole Dipole interactions
Dispersion Forces
1.
‐only IMF among Noble gas atoms and nonpolar molecules (resulting in their low BP)‐force increases with mass
‐attraction between polar molecules (dipoles)
‐a temporary dipole moment is created
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2. Hydrogen Bonds
H‐FH‐OH‐N
‐H bonded to strongly EN atom
‐Strongest of IMF
Covalent Network Solids