1. Bonding in Covalent Molecules
Dispersion Forces
Dipole-Dipole Attraction
Hydrogen Bonding
For information on these 3 types of bonding, see the word doc in the folder labelled ‘Types of bonding in covalent molecules’

2. Polarity and Shape of Molecule
Polarity with reasons
Intermolecular Force
Methane
𝑪𝑪𝒍 𝟒
For notes, see the
Word doc in the folder labelled ‘Polarity and shapes of molecules’
Ammonia
Water
Hydrogen chloride
Carbon Dioxide
Oxygen, Nitrogen molecules

3. Allotropes of Carbon
Diamond, graphite and buckeyballs (or fullerenes) are allotropes of carbon.
All 3 are made of C atoms but are arranged differently. Hence their properties differ.
For example, diamond does not conduct electricity but graphite does, etc.

4. Structures of covalent compounds and their properties.
1. Covalent Network Lattice
Example:
Diamond
Silicon Dioxide (or Quartz)

5. 1. Covalent Network Lattice
Each atom is bonded to many other atoms by strong covalent bonds in a 3-D network lattice. As a result:
Have high mpts/bpts, hard, brittle, non- conductors of electricity and insoluble in water.

6. Covalent Network
Example: Diamond – is one giant structure (macromolecule). The C atoms are arranged in a tetrahedral position by strong intramolecular covalent bonds .

7. Covalent Network
Example: Quartz (Silicon Dioxide)

8. 2. Covalent Layer Lattice
Example
Graphite
In this type of structure, each atom is held by strong covalent bonds in a hexagonal position as a layer.
The layers are held by the weak dispersion forces. Hence the layers slide over each other; slippery
High mpts/bpts, layers slide, good conductors of electricity due to delocalised e’s between layers.

9. 2. Covalent Layer Lattice
Example
Buckeyballs
Are molecules of carbon arranged in a hollow sphere.
Most common one is called 𝑪 𝟔𝟎 where the C atoms are arranged in hexagonal and pentagonal rings by strong covalent boding, shaped like a soccer ball.
Solids at room temperature, low mpts, soft and resistant to collision.

10. 3. Discrete Molecules Example
Short molecules held by weak dispersion forces that break at low temperatures. (low mpts/bpts)
Non-conductors of electricity as they are neutral (no charges as they are SYMMETRICAL and hence non-polar molecules.)
Since they are non-polar substances, they will generally dissolve in non- polar solvents. LIKE dissolves LIKE.