Summary of "A Level Chemistry Revision "Properties of Ionic Compounds"."

Summary of “A Level Chemistry Revision: Properties of Ionic Compounds”

Main Ideas and Concepts

Formation of Ionic Compounds

Ionic compounds form a giant ionic lattice structure. This lattice consists of a large number of ions arranged so that each ion is attracted to oppositely charged ions by electrostatic forces of attraction.

Properties of Ionic Compounds Explained by the Giant Ionic Lattice

High Melting and Boiling Points Ionic compounds have very high melting and boiling points because a large amount of energy is required to overcome the strong electrostatic forces holding the ions together. Examples:
- Sodium chloride melts at 801°C.
- Magnesium oxide melts at 2852°C due to stronger forces, as Mg²⁺ and O²⁻ ions have greater charges, leading to stronger attraction.
Solubility in Polar Solvents Ionic compounds tend to dissolve in polar solvents like water. Water molecules surround and separate the ions, overcoming the electrostatic attractions. However, as ionic charge increases (e.g., MgO), solubility decreases because water molecules cannot overcome the stronger ionic attractions.
Electrical Conductivity
- Ionic compounds do not conduct electricity when solid because ions are fixed in place and cannot move.
- When melted or dissolved in water, ionic compounds can conduct electricity since ions are free to move and carry charge.

Summary of Methodology/Explanation

Describe the formation of a giant ionic lattice.
Explain electrostatic forces between ions.
Use the lattice structure to explain:
- Melting and boiling points (energy needed to overcome forces).
- Solubility in polar solvents (interaction with water molecules).
- Electrical conductivity in solid vs molten/dissolved states.