Overview
This lecture explains how ionic bonds form through the transfer of electrons between atoms, using examples such as sodium chloride, magnesium oxide, and calcium chloride.
Formation of Ions
- Ions form when atoms lose or gain electrons.
- Electrons are transferred from one atom to another, not created or destroyed.
Ionic Bond Formation
- Sodium loses one electron to chlorine, forming Na⁺ and Cl⁻ ions.
- The opposite charges of Na⁺ and Cl⁻ cause electrostatic attraction, known as an ionic bond.
- Ionic bonds are like the attraction between opposite poles of a magnet.
Examples of Ionic Compounds
- Sodium chloride (NaCl) is held together by ionic bonds between Na⁺ and Cl⁻.
- Magnesium transfers two electrons to oxygen, forming Mg²⁺ and O²⁻ ions in magnesium oxide (MgO).
- Calcium loses two electrons, each transferred to a separate chlorine atom, forming Ca²⁺ and two Cl⁻ ions in calcium chloride (CaCl₂).
Charge Balance in Ionic Compounds
- The total positive and negative charges in an ionic compound must balance out.
- All three discussed compounds (NaCl, MgO, CaCl₂) are electrically neutral because their ions’ charges balance.
Key Terms & Definitions
- Ion — an atom or molecule with a net electric charge due to loss or gain of electrons.
- Ionic bond — electrostatic attraction between oppositely charged ions.
- Electrostatic attraction — the force pulling together opposite charges.
Action Items / Next Steps
- Draw the ionic compound magnesium oxide showing the transfer of electrons and correct charges on ions.
- Ensure all future diagrams of ionic compounds include the charges on each ion.