1. Covalent Properties and Forces
February 2015

2. How do you tell if a molecule is polar?

3. Properties of Covalent Compounds
Differences in properties is a result of differences in attractive forces
In a covalent compound
Bond between atoms is relatively strong
Bond between molecules is relatively weak
Bonds between molecules are known as intermolecular forces or van der Waals forces

4. Intermolecular Forces
Dispersion force
Between nonpolar molecules
Dipole-Dipole force
Between oppositely charged ends of two polar molecules
More polar the molecules the stronger the dipole- dipole force is
Hydrogen Bond
Between hydrogen end of one dipole and a F, O, or N atom on another dipole

5. Properties from forces
Low melting points and boiling points
Exist as gases or vaporize readily at room temperature
Hardness depends on intermolecular force
Relatively soft solids
Solid phase
Form crystal lattice
Crystal shape depends on molecular shape

6. Covalent Network Solids
Atoms interconnected by a network of covalent bonds
Quartz and diamond
Contrast molecular solids
Typically brittle
Non conductors of heat or electricity
Extremely hard
Diamond
Carbon atom bonded to 4 other carbons
Tetrahedral crystal – extremely hard and very high melting point

7. Comic Assignment due Friday 2/11
STORY - Choose one type of bonding and write “A Day in the Life of an Atom” story describing what it's like to be an atom that forms your chosen bond type. The story should incorporate at least 5 properties from your bonding. (you may do a song or poem as well)
COMIC STRIP - Choose one type of bonding and write a comic strip with 3+ frames. The comic should incorporate at least 3 properties.
SINGLE-FRAME CARTOON - Draw a single-frame cartoon for each type of bonding. Each cartoon should incorporate at least one key property from your Bonding.

8. Example