1. Unit 6
Covalent Bonding

2. Lesson1 :Covalent Bonding
Covalent bonds: atoms held together by sharing electrons.
Molecules: neutral group of atoms joined together by covalent bonds.
Diatomic molecule: molecule consisting of 2 atoms. Remember them: F2, Cl2, I2, Br2, H2, N2, O2
Molecules tend to have lower melting and boiling points than ionic compounds.
YouTube - Making Molecules with Atoms

3. Molecular Formula
Shows how many atoms of each element a molecule contains.
Naming binary molecular compounds
Composed of two nonmetals; often combine in more than one way. Ex. CO and CO2
Prefixes are used to name binary molecular compounds.
Prefix
Mono-
Di-
Tri-
Tetra-
Penta-
Hexa-
Hepta-
Octa-
Nona-
Deca-
Number 1 2 3 4 5 6 7 8 9 10

4. Binary Compounds Containing Two Nonmetals
To name these compounds:
give the name of the less electronegative element first with the Greek prefix indicating the number of atoms of that element present
After give the name of the more electronegative non-metal with the Greek prefix indicating the number of atoms of that element present and with its ending replaced by the suffix –ide.
Do not use the prefix mono- if required for the first element.

5. Binary Molecular Compounds
N2O dinitrogen monoxide
N2O3 dinitrogen trioxide
N2O5 dinitrogen pentoxide
ICl iodine monochloride
ICl3 iodine trichloride
SO2 sulfur dioxide
SO3 sulfur trioxide
YouTube - Naming molecular compounds

6. Binary Molecular Compounds Containing Two Nonmetals
As2S3
________________ diarsenic trisulfide
________________ sulfur dioxide
P2O5 ____________________
________________ carbon dioxide
N2O5 ____________________
H2O ____________________
SO2
diphosphorus pentoxide
CO2
dinitrogen pentoxide
dihydrogen monoxide

7. Naming Binary Compounds
Yes
Metal Present? No
Yes
Molecule
Use Greek
Prefixes
Does the metal form
more than one cation? No
Yes
Ionic compound (cation has more
than one charge) Determine the
Charge of the cation; use a Roman
numeral after the cation name.
Ionic compound (cation has
one charge only)
Use the element
name for the cation.
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 98

8. Classwork #1: Do handout “Naming Molecules”