Notes on Physical Properties of Simple Covalent Molecules

Covalent Substances: These exist in various forms, with simple covalent molecules being one specific structure.
Physical Properties of Simple Covalent Molecules:
- Melting and Boiling Points:
- Simple covalent molecules have low melting and boiling points.
- A small amount of energy is required to overcome weak intermolecular forces, resulting in gaseous or liquid states at room temperature and pressure (r.t.p).
- Solubility:
- Most simple covalent molecules are insoluble in water but soluble in organic solvents.
- Electrical Conductivity:
- Generally poor conductors of electricity due to the lack of free-moving charged particles.

Strong Covalent Bonds: The atoms within a simple covalent molecule are held together by strong covalent bonds.
Weak Intermolecular Forces: The molecules themselves are attracted to one another by weak intermolecular forces of attraction.
- These weak forces require little energy to overcome, leading to the low melting and boiling points of simple covalent substances.

Bromine (Br): A simple covalent molecule that remains liquid at room temperature.
- Exhibits low melting and boiling points due to weak intermolecular forces.
Iodine (I): A larger molecule than bromine, which exists as a solid at room temperature.
- This increased size results in stronger intermolecular forces, leading to higher melting and boiling points compared to bromine.