1. Molecules & Covalent Bonding

2. Recall Bonding between two atoms can either refer to the transfer or sharing of electrons. In an ionic bond, the electrons transfer from the metal to the non-metal. Today we will look at the sharing of electrons: covalent bonding.

3. Molecular Compounds A molecule is a combination of two or more atoms held together by covalent bonds. Occurs between two or more non-metal atoms. The shared electrons belong to both atoms creating a full valence shell. The force of attraction for these mutual electrons holds the atoms together.

4. Nomenclature Naming molecular compounds is done in three steps: 1. Write the left-most atom first 2. Change the suffix of the right-most atom to “-ide”. 3. Apply appropriate prefixes where necessary.

5. Common Prefixes Prefix # of atoms Mono-1 Di-2 Tri-3 Tetra-4 Penta-5 Hexa-6 Hepta-7 Octa-8 Nona-9 Deca-10 *Note: Mono is only used for the second atom in the compound.

6. Example #1 For the molecular compounds formed by the atoms below i. Draw the Lewis diagrams of the resulting molecule ii. Write the chemical formula iii. Write the chemical name a) H & F HF H F HF Covalent Bond (shared electron pair) ii) HF iii) Hydrogen monofluoride i) b) O & O OO OO OO ii) O 2 iii) Dioxide Note: An example of a diatomic molecule.

7. c) C & Cl CCl C ii) CCl 4 iii) Carbon tetrachloride

8. Example #2 Determine the chemical formula for the following molecular compounds. a) Dihydrogen Monoxide b) Carbon Dioxide c) Dicarbon Hexahydride H2OH2OCO 2 C2H6C2H6

9. Example #3 Determine the chemical name for the following molecular compounds. a) CBr 4 b) S 2 O 5 c) C 3 H 8 Carbon tetrabromide Disulphur pentoxide Tricarbon octahydride

10. Building Molecular Models On a separate sheet of paper, create the following chart (1 whole page). AtomsSketch Formula & Name Lewis Diagrams H & H O & O C & four H O & two H H & Cl N & three H

11. Homework P.212 #1-3 Naming Molecular Compounds (web-site)