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