Chapter 3: Ions, Ionic Compounds, and Nomenclature

Overview of Ions

• Definition: Ions are particles with an electrical charge.
  • Simple ions: Charged atoms, e.g., Na⁺, Ca²⁺
  • Polyatomic ions: Small charged molecules, e.g., NH₄⁺, CO₃²⁻
• Cations (positively charged)
• Anions (negatively charged)

Position on the Periodic Table

• Elements' position can help determine type and charge of ion.
• Metals (left of the bold staircase line): Typically form cations.
• Non-metals (right of the line): Typically form anions.

Group Characteristics

• Group I A (1): Cations with +1 charge
• Group II A (2): Cations with +2 charge
• Transition Metals (Groups III B to II B, 3-12): Variable charges, +2 or +3 common
• Group III A (13): Metals form +3 charge cations
• Group IV A (14): Metals form +4 charge cations; exceptions include tin (Sn) and lead (Pb) which can also have +2 charge
• Group V A (15): Non-metals form -3 charge anions
• Group VI (16): Non-metals form -2 charge anions
• Group VII A (17): Form -1 charge anions
• Group VIII A (18): Typically uncharged

Nomenclature of Simple Ions

• Cations: Element name + 'ion', e.g., Na⁺ is sodium ion
  • Transition metal cations: Include charge in parenthesis, e.g., Fe(III)
• Anions: Element name ends in 'ide', e.g., Cl⁻ is chloride ion

Polyatomic Ions

• Cations:
  • NH₄⁺: Ammonium ion
  • H₃O⁺: Hydronium ion
• Anions:
  • OH⁻: Hydroxide ion
  • CO₃²⁻: Carbonate ion
  • SO₄²⁻: Sulfate ion
  • PO₄³⁻: Phosphate ion
  • ClO⁻: Hypochlorite ion

Special Case: Hydrogen

• Hydrogen can form both cations (H⁺) and anions (H⁻)
• Typically does not form ions with non-metals

Ionic Compounds

• Definition: Composed of oppositely charged ions held by Coulombic forces
• Types:
  • Simple ionic compounds: Consist of simple ions
  • Complex ionic compounds: Include polyatomic ions
• Chemical Formula: Cation first, followed by anion
  • E.g., Na₂CO₃ for sodium carbonate
• Naming: Name the cation, then the anion without 'ion' suffix

Important Rules

• Electrically Neutral Compounds: Sum of positive charges must equal sum of negative charges
• Naming Transition Metal Compounds: Include Roman numeral for charge, e.g., FeCl₃ is iron (III) chloride

Vocabulary

• Ion: A charged particle
• Simple Ion: A single atom with a charge
• Polyatomic Ion: A molecule with a charge
• Cation: Positively charged ion
• Anion: Negatively charged ion

Homework Assignments

1. Write formulas and names for ions of given elements.
2. Write chemical formulas for given ion names.
3. Formulate ionic compounds from given cations and anions.
4. Determine ions in given compounds and name the compound.
5. Write correct formulas for named compounds.

Answers Provided for Homework

• Includes examples of ions and compounds with their respective charges and names.