* Ions: Ions are atoms or molecules that have gained or lost electrons, resulting in a net electrical charge.
* Cations: Positively charged ions (formed when an atom loses electrons).
* Anions: Negatively charged ions (formed when an atom gains electrons).
* Ionic Bonding: The strong electrostatic attraction between oppositely charged ions holds them together in a rigid, crystalline structure.
Key Characteristics of Ionic Compounds:
* High Melting and Boiling Points: The strong ionic bonds require a lot of energy to break, resulting in high melting and boiling points.
* Hard and Brittle: The rigid crystalline structure makes them hard, but the ions can easily slide past each other under pressure, leading to brittleness.
* Good Conductors of Electricity in Molten State or Solution: When molten or dissolved in a solvent, the ions can move freely, allowing for the conduction of electricity.
* Generally Soluble in Water: The polar water molecules can surround and separate the ions, dissolving the compound.
Examples of Ionic Compounds:
* Sodium Chloride (NaCl): Common table salt, composed of sodium cations (Na+) and chloride anions (Cl-).
* Calcium Carbonate (CaCO3): The main component of limestone and seashells, formed by calcium cations (Ca2+) and carbonate anions (CO32-).
* Magnesium Oxide (MgO): A white solid used in various applications, including as a dietary supplement, composed of magnesium cations (Mg2+) and oxide anions (O2-).
Formation of Ionic Compounds:
Ionic compounds typically form when a metal atom (tending to lose electrons) reacts with a nonmetal atom (tending to gain electrons). The metal atom loses electrons to become a cation, and the nonmetal atom gains electrons to become an anion. These oppositely charged ions then attract each other to form the ionic compound.
