Chemistry
Chapter 9
Notes #4
Chapter 9 – Quick Review
• Covalent Bonds
– Sharing of electrons
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Naming Molecules
Writing Formulas
Naming Acids/Writing Formulas
Molecular Geometry
Hybridization
Polarity
Types of intermolecular forces
Hybridization
• A process where atomic orbitals are mixed to
form new identical “hybrid” orbitals
• Example = Carbon
Carbon’s outer
energy level =2
The s sublevel
is full and the p
sublevel has 2
Hybridization
• If carbon undergoes hybridization the 4 e- in
energy level 2 all go to separate orbitals
Carbon now has 4 e- that are ready to
make bonds. 1s orbital and 3 p orbitals.
Name= sp3
Polarity
• Electron Affinity
– measure of the tendency of an atom to accept
an e– Increases as you move to the right and up on
the periodic table…
• Electronegativity
– Ability of an atom to attract e- in a chemical
bond
– Increases as you move to the right and up on
the periodic table…
Polarity
• Nonpolar covalent bonds
– When 2 atoms bond and the difference in their
electronegativity values are zero
– Equal sharing of electrons between 2 atoms
– Most commonly occurs in 2 identical atoms
bonding together
• Ex. O2, H2, N2, F2, Cl2, etc.
• Each of these is called a diatomic molecule
• Add to cheat sheet (halogens, O, H, N)
Polarity
• Polar Covalent Bonds
– Unequal sharing of electrons
– One electron is winning the tug of war over
the shared electrons
• It is winning because it has a much stronger
electronegativity
• If the difference in e- is greater than 0.4 = polar
– Ex.
H-Cl
Polarity
Polarity
• The polarity of each bond is decided by
subtracting the electronegativities of each atom
involved in the bond
• The polarity of a molecule is based on shape
– Symmetric shapes = nonpolar
– Asymmetric shapes = polar
Intermolecular Forces
• 1.Dispersion Forces
– Occurs between nonpolar substances
– Attraction between molecules is weak
• 2. Dipole-Dipole Forces
– Occurs between polar substances
– Stronger than dispersion
• 3. Hydrogen Bond
– Especially strong attraction between H and F,
O, or N