Lecture on Ionic Bonding

Introduction

• Focus on ionic bonding in detail.
• Recap on basic fundamentals using sodium chloride.
• Importance of understanding electron arrangements in atoms for ionic bonding.

Electron Arrangement

• Electrons reside in specific locations in an atom.
• Diagram Explanation: Shows electron spots arranged in rings around the nucleus.
  • Rings are referred to as shells or energy levels.
• Determines where electrons are in sodium and chlorine.

Atomic Structure

• Sodium (Na)
  • Atomic number: 11 (11 protons and 11 electrons).
  • Neutral atoms: equal number of protons and electrons.
• Chlorine (Cl)
  • Atomic number: 17 (17 protons and 17 electrons).
  • Starts without charge, also neutral.

Valence Shells

• Definition: Furthest energy level with electrons.
• Sodium
  • One electron in its valence shell.
  • Unhappy due to 7 empty spots.
• Chlorine
  • Nearly full valence shell with one empty spot.
  • Seeks to fill it for stability.

Formation of Ionic Bonds

• Interaction: Sodium and chlorine help each other achieve full valence shells.
  • Sodium donates one electron to chlorine.
  • Electron transfer: sodium -> chlorine.
  • Results in: Chlorine's valence shell is full.
• Sodium’s New Valence Shell
  • Loses its outer electron shell, revealing a full inner shell.
• Outcomes
  • Sodium: Full new valence shell by losing outer electron.
  • Chlorine: Achieves full valence shell by gaining electron.

Ion Formation

• Chlorine
  • Gains an electron (total electrons = 18, protons = 17).
  • Acquires a negative charge (1-), becomes an anion.
• Sodium
  • Loses an electron (total electrons = 10, protons = 11).
  • Acquires a positive charge (1+), becomes a cation.

Attraction and Bond Formation

• Opposite charges attract.
• Sodium Chloride Formation
  • Positively charged sodium (Na⁺) and negatively charged chloride (Cl⁻) stick together.

Summary

• Key Steps
  • Sodium and chlorine start neutral.
  • Electron moves from sodium to chlorine.
  • Chlorine ends with full valence shell and a 1- charge.
  • Sodium ends with a full inner valence shell and a 1+ charge.
• Concept Understanding
  • Important to grasp electron movement for understanding ionic bonds.
  • Encouraged to review material for clarity before advancing.