Recording-2025-02-20T22:00:26.975Z

Introduction to Compounds

• Compounds are formed when two or more atoms come together, resulting in unique properties that differ from the individual atoms.

Types of Bonds

• Ionic Bonds: Formed between cations (positively charged ions) and anions (negatively charged ions), held together by the charge difference.

• Covalent Bonds (also called Molecular Bonds): Occur between two or more nonmetals that share electrons.

Examples of Compounds

• Water (H2O): Formed from hydrogen and oxygen gases.

• Sodium Chloride (NaCl): Common table salt, representing an ionic compound with unique properties.

• Crystal structure of salts illustrates that ionic compounds are not merely a one-to-one interaction but rather a lattice structure with multiple ions arranged in a repeating pattern.

Lattice Energy

• The energy released when ionic compounds form could be referred to as lattice energy;

• Factors influencing lattice energy:

  • Ion Size: Larger ions lead to weaker attractions and lower lattice energy.

  • Charge of Ions: Greater charges result in stronger attractions and higher lattice energy.

• Example: Lithium Chloride vs Cesium Chloride: Lithium has a smaller ionic radius, thus stronger attraction than the larger cesium.

Determining Charges of Main Group Elements

• Knowing the periodic table helps determine the charge of elements:

  • Group 1: +1 charge

  • Group 2: +2 charge

  • Group 3: +3 charge

  • Group 4: Rarely forms ionic compounds, usually shares electrons.

  • Group 5: -3 charge