Lecture on Atomic Structure: Shells, Subshells, and Orbitals

Introduction

• Topics Covered: Shells (Energy Levels), Subshells, and Orbitals
• Purpose: Simplified visualization using Bohr's model

Bohr Model

• Analogy: Electrons orbit nucleus like planets orbit the sun
• Why Electrons Orbit: Attraction between negatively charged electrons and positively charged protons
• Energy Levels: Adding energy moves electrons to higher levels further from nucleus
• Components:
  • Nucleus: Protons and Neutrons
  • Electrons: Orbiting the nucleus
• Principal Quantum Numbers: Used to label energy levels (1, 2, 3, ...)
  • Represented by 'N'
  • Higher N = Further from nucleus
  • N = 1 is closest to nucleus
• Energy Level Capacity:
  • 1st Level: up to 2 electrons
  • 2nd Level: up to 8 electrons
  • 3rd Level: up to 18 electrons
  • Formula: 2n² (n = energy level number)

Calculating Electron Capacity

• **Example Calculations: **
  • 2nd Shell: n=2 → 2(2²) = 8 electrons
  • 4th Shell: n=4 → 2(4²) = 32 electrons

Subshells

• Definition: Sub-levels within energy levels
• Types of Subshells: S, P, D, F
• Mnemonic: Keyboard layout to remember order
• Energy Level Subshells:
  • Level 1 (N=1): S
  • Level 2 (N=2): S, P
  • Level 3 (N=3): S, P, D
  • Level 4 (N=4): S, P, D, F
• Relationship: N number equals the number of sublevels

Orbitals

• Definition: Precise locations for electrons within subshells
• Capacity: Each orbital can hold up to 2 electrons
• Subshell Orbital Counts:
  • S: 1 orbital (2 electrons)
  • P: 3 orbitals (6 electrons)
  • D: 5 orbitals (10 electrons)
  • F: 7 orbitals (14 electrons)

Summary

• Tree Diagram: Visual aid to understand hierarchy:
  • Top Row: Energy Levels
  • Second Row: Sublevels
  • Third Row: Orbitals
  • Bottom Row: Electrons per sublevel

Conclusion

• Key Points:
  • Energy levels (shells) and subshells
  • Orbitals and electron capacity
• Next Steps: Continuing exploration of atomic structure
• Reminder: Like, subscribe, and share the content
• Farewell: "Have a good one!"