Key Concepts in Chemical Bonds and Compounds

Periodic Table of Elements

  • Contains approximately 100 known elements.

  • Organized into groups (alkali metals, alkaline earth metals, transition metals, etc.).

Compounds

  • Chemical combinations of elements with distinct properties.

  • Most matter is made of compounds.

  • A compound is a pure substance, combining two or more elements.

  • Example of a compound: water (H₂O), sugar (C₁₂H₂₂O₁₁).

Chemical Formulas

  • Chemical formulas reveal elements and atom ratios in a compound.

  • Example formulas: NaCl (Sodium Chloride), H₂SO₄ (Sulfuric Acid).

Properties of Compounds

  • Compounds have different properties than their constituent elements.

  • Example: Sodium (metal) + Chlorine (gas) = Sodium Chloride (solid).

Types of Chemical Bonds

  • Ionic Bond: Metal atom transfers electron to nonmetal atom.

  • Covalent Bond: Nonmetal atoms share electrons.

  • Metallic Bond: Electrons move freely in metal lattice.

Ionic Compounds

  • Formed by ionic bonds between metals and nonmetals.

  • Characterized by high melting and boiling points.

  • Conduct electricity when molten or in solution.

  • Example: MgO (Magnesium Oxide) and MgF₂ (Magnesium Fluoride).

Properties of Ionic Compounds

  • Usually form crystalline solids.

  • Brittle and break easily.

  • Generally soluble in water.

Lewis Dot Diagrams

  • Represent atoms and their valence electrons.

  • Valence electrons determine bonding capacity.

  • Maximum of eight electrons shown around atomic symbol.