Naming Compounds with Polyatomic Ions

Introduction

• Presenter: Melissa Maribel, personal tutor.
• Topic: How to name compounds with polyatomic ions.
• Emphasis on both finding chemical formulas from names and vice versa.

Important Points for Naming Compounds

1. Ionic Compounds with Polyatomic Ions

   • Name consists of the metal's name followed by the polyatomic ion's name.
   • Everything in lowercase.

2. Balancing Charges

   • Necessary for finding chemical formulas.
   • Memorize charges of common ions.

3. Polyatomic Ions Definition

   • Composed of two or more atoms.
   • Have an overall charge.
   • Important to know common polyatomic ions (often provided by teachers).

Examples

Example 1: Same Charges

• Problem: Convert magnesium carbonate to chemical formula.
  • Magnesium (Mg) has a 2+ charge.
  • Carbonate (CO3) has a 2- charge.
  • Result: No subscript needed as charges are balanced.
  • Reverse: Li (Lithium) and C2H3O2 (Acetate) gives lithium acetate.

Example 2: Different Charges

• Problem: Convert aluminum sulfate to chemical formula.
  • Aluminum (Al) has a 3+ charge.
  • Sulfate (SO4) has a 2- charge.
  • Solution: Balance by making sulfate subscript '3' and aluminum subscript '2'.
    • Use parentheses for polyatomic ions with subscripts.
  • Reverse: Ca (Calcium) and OH (Hydroxide) gives calcium hydroxide.

Example 3: Both Polyatomic Ions

• Problem: Convert ammonium sulfate to chemical formula.
  • Ammonium (NH4) has a 1+ charge.
  • Sulfate (SO4) has a 2- charge.
  • Solution: Ammonium in parentheses with subscript '2', followed by SO4.
  • Reverse: NH4 (Ammonium) and NO3 (Nitrate) gives ammonium nitrate.

Memorization Trick

• Polyatomic Ions Ending:
  • Most end in "ite" or "ate".
  • "Ate" ions have one more oxygen than "ite".
  • Strategy: Focus on memorizing "ate" ions to simplify learning.

Additional Resources

• Videos & Guides: Detailed examples and explanations available.
• Notes & Tools: 30-page guide on naming compounds and acids, additional resources for homework and tutoring.
• Motivation: "Stay determined, you can do this!"