Free Science Lessons: Ionic Bonding

Objectives

• Understand how electrons are transferred during ionic bonding.
• Learn to draw dot and cross diagrams to represent ionic bonding.

Electron Configuration Recap

• Electrons exist in energy levels or shells.
• Maximum electrons per energy level:
  • 1st level: 2 electrons
  • 2nd level: 8 electrons
  • 3rd level: 8 electrons (before the 4th starts filling)
• Noble Gases (Group 0):
  • Have a full outer energy level, making them stable and unreactive.

Ionic Bonding Overview

• Purpose: Elements react to achieve a full outer energy level, mimicking the stable electronic structure of noble gases.
• Periodic Table:
  • Metals are on the left side.
  • Non-metals are on the right side.
• Ionic Bonding:
  • Occurs when a metal reacts with a non-metal.
  • Example: Group 1 metal (e.g., Lithium) with Group 7 non-metal (e.g., Fluorine).

Ionic Bonding Example: Lithium and Fluorine

• Lithium Atom:
  • 3 electrons: 2 in the 1st energy level, 1 in the outer level.
  • 3 positive protons, resulting in no overall charge.
• Fluorine Atom:
  • 9 electrons: 2 in the 1st energy level, 7 in the outer level.
  • 9 positive protons, resulting in no overall charge.
• Reaction Process:
  • Lithium loses its outer electron to Fluorine.
  • Resulting Ions:
    • Lithium becomes a positive ion (loses 1 electron): Li⁺
    • Fluorine becomes a negative ion (gains 1 electron): F⁻
  • Both ions achieve a full outer energy level.

Key Concepts

• Group 1 Metals lose 1 electron, forming a 1+ ion.
• Group 7 Non-metals gain 1 electron, forming a 1- ion.
• Resulting ions have stable electronic structures.

Exam Strategy

• Typical Exam Question:
  • Describe electron transfer in the reaction between sodium (Group 1) and chlorine (Group 7).
  • Use dot and cross diagrams to illustrate only the outer energy levels.
  • Key points to include:
    • Electron transfer from sodium to chlorine.
    • Both achieve full outer energy levels.

Additional Resources

• Practice questions available in the revision workbook.