1. Molecular Bonding and Nomenclature

2. Molecular Bonding Binary molecular compounds form between 2 non-metals
Covalent bonds: shared electrons
Each atom counts the electrons as part of their octet
Molecular formula: shows number and kind of atoms in a molecule

3. Molecular Naming
Use a prefix to identify the number of atoms present in the molecule
1: mono 2: di 3: tri
4: tetra 5: penta 6: hexa
7: hepta 8: octa 9: nona
10: deca
Second element in name ends with –ide
If only one of the first element do not need mono-

4. Questions How does molecular bonding differ from ionic bonding?
Why must a prefix be used to distinguish between CO and CO2?

5. Writing Molecular Formulas
Use prefix to determine the number of atoms
Write the subscript behind the atom in the formula to show the number of atoms

6. Covalent Bonds
Single Covalent Bonds: 2 atoms share a pair of electrons so that each achieves an octet
F2 NH3

7. Covalent Bonds
Double Covalent bond: 2 atoms share 2 pairs of electrons O2
Triple Covalent Bond: 2 atoms share 3 pairs of electrons N2

8. Structural Formula
Shows the arrangement of atoms in a molecule or a polyatomic ion
The pair of shared electrons is represented as a dash
H2 H-H
Practice: NH3 F2 N2

9. Exceptions to the Octet Rule
BF3 Boron is stable with 6 electrons in its valence shell
P and S sometimes expand their octet to include 10 or 12 electrons.
PCl3, PCl5, SF6

10. Polar Covalent Bonds
Sometimes electrons are not shared equally in a covalent bond
Atom with higher electronegativity draws electrons toward itself, pulling those electrons away from the atom of lower electronegativity.
Unequal charge distribution

11. Polar Covalent Example
HBr
Electronegativity of H is 2.1
Electronegativity of Br is 2.8
Br pulls the bonding electrons toward itself
Results in a polar bond.
Br is slightly negative
H is slightly positive