Understanding Elements and Compounds

Nov 28, 2024

Lecture Notes: Elements and Compounds

Introduction

  • Focus: Naming Compounds
  • Key Terms: Elements, Compounds, Binary Ionic Compounds, Polyatomic Ions, Binary Covalent Compounds, Acids, Hydrated Compounds

Elements

  • Found on the Periodic Table (118 elements)
  • Definition: Molecules made up of the same atoms
    • Examples: Oxygen, Hydrogen, Chlorine, Bromine, Iodine, Ozone
  • Classification:
    • Metals: High melting points, conduct electricity
    • Non-metals: Covalent compounds
    • Metalloids: Characteristics of both metals and non-metals

Compounds

Naming Compounds

Binary Ionic Compounds

  • Definition: Ionic compounds made of two elements
  • Examples:
    • Potassium Fluoride (K-F)
    • Sodium Nitrite (Na-N)
    • Calcium Phosphide (Ca-P)
  • Naming Rules:
    • First name is the metal
    • Second name ends with '-ide'
    • Example: Fluorine -> Fluoride

Polyatomic Ions

  • Definition: Ions made of multiple atoms
  • Characteristics:
    • Can be part of ionic compounds
    • Not necessarily different types of atoms
  • Examples:
    • More than one atom forms the ion

Naming Ionic Compounds

  • Formulas: Balance charges between ions
    • Example: Lithium Hydroxide (LiOH)
  • Naming: Positive ion first, then the negative
    • Example: Calcium Chloride (CaCl₂)

Binary Covalent Compounds

  • Definition: Compounds made of two different atoms
  • Naming Rules:
    • First element as is
    • Use prefixes (mono, di, tri) for second element
    • '-ide' suffix to the second element
    • Exceptions for single first element: No 'mono' prefix

Acids

Binary Acids

  • Definition: Compounds with hydrogen and one other element
  • Examples:
    • HCl (Hydrochloric Acid)
    • HBr (Hydrobromic Acid)
  • Naming: Different depending on state (aqueous or liquid)

Oxy Acids (Oxo Acids)

  • Definition: Acids containing oxygen
  • Examples:
    • Nitric Acid (HNO₃)
    • Sulfuric Acid (H₂SO₄)
  • Naming:
    • '-ic' for acids with more oxygen
    • '-ous' for acids with less oxygen

Hydrated Compounds

  • Definition: Compounds with water molecules attached
  • Example: Copper (II) Sulfate Pentahydrate
    • Water molecules physically attached to the compound
    • Heating evaporates water

Study Tips

  • Memorization of names and formulas is beneficial
  • Practice via guided learning and revision questions