Topic: Properties of Small Molecules

Part 1 - Keywords:

1. Small molecules

2. Intermolecular forces

3. Melting points

4. Boiling points

5. Covalent bonds

6. Electric charge

7. Conductivity

Part 2 - Key Facts:

• Substances composed of small molecules are typically gases or liquids with low melting and boiling points.

• Weak intermolecular forces exist between the molecules, which are overcome during melting or boiling, not the covalent bonds.

• The strength of intermolecular forces increases with the size of the molecules, resulting in higher melting and boiling points for larger molecules.

• Small molecule substances do not conduct electricity as their molecules lack an overall electric charge.

• Interpreting intermolecular forces as weaker compared to covalent bonds helps explain the bulk properties of molecular substances.

Part 3 - Quick Quiz:

1. What type of substances usually consist of small molecules?

   a) Solids

   b) Gases and liquids

   c) Polymers

   Answer: b) Gases and liquids

2. What forces are overcome during the melting or boiling of small molecule substances?

   a) Covalent bonds

   b) Metallic bonds

   c) Intermolecular forces

   Answer: c) Intermolecular forces

3. Why do larger molecules have higher melting and boiling points compared to smaller molecules?

   a) They have stronger covalent bonds

   b) They have weaker intermolecular forces

   c) They have stronger intermolecular forces

   Answer: c) They have stronger intermolecular forces

Part 4 - Going Further: Explain the concept of intermolecular forces and how they contribute to the physical properties of small molecule substances. Provide examples to illustrate the relationship between molecular size, intermolecular forces, and melting/boiling points.

Part 5 - Revision Tips: To understand the properties of small molecules, practice comparing the strength of intermolecular forces between different substances. Create charts or diagrams to visualise these relationships.

Part 6 - More Help: