Atomic Structures Lecture Notes

Lecture Overview

• Focus on atomic structures as part of the H2 syllabus.
• Lecture divided into three sections:
  • Lecture 1: Content points 1 and 2
  • Lecture 2: Points 3 and 4
  • Lecture 3: Point 5

Evolution of the Atomic Model

• Students should watch a recommended video (page 3 of lecture notes) on the development of atomic models.
• Final model discussed: Quantum Model by A. Wind.

Section 1.2: Fundamental Subatomic Particles

• Atoms: Smallest particle of an element retaining chemical properties.
• Nucleus Composition:
  • Protons and Neutrons (nucleons)
• Electron Orbitals: Negatively charged electrons occupying space around the nucleus.
• Electrostatic Forces: Attraction between protons and electrons.
• Subatomic Particles Table:
  • Relative charges, rest mass (in kg), relative mass, and location.
• Difference between Rest Mass and Relative Mass:
  • Relative mass has no units, is a ratio (e.g., proton:neutron:electron = 1:1:1/1840).
  • Rest mass has units (e.g., proton = 1.67 x 10^-27 kg).
• Data Booklet Reference: Page 1 for rest mass values.

Section 1.3: Behavior in Electric Fields

• Electric Field: Shown by lines between positive and negative plates.
• Deflection of Particles:
  • Electrons (negatively charged) deflected towards positive plate.
  • Protons (positively charged) deflected towards negative plate.
  • Neutrons (neutral) not deflected.
• Angle of Deflection:
  • Depends on charge/mass ratio.
  • Greater angle for particles with lighter mass or higher charge (e.g., electrons).
• Self-check Questions: Available on Google Drive. Not discussed in tutorials.

Section 1.4: Determining Subatomic Numbers

• Proton Number: Identity of the element.
• Atomic Representation: Symbol, nucleon number (mass number), atomic number (proton number).
• Neutral Atoms:
  • Protons = Electrons
• Ions:
  • Anions: More electrons (protons + 1)
  • Cations: Fewer electrons (protons - 1)
• Self-check Questions: Attempt questions 2-4 to reinforce learning.

Section 1.5: Isotopes

• Definition: Atoms of the same element with the same number of protons but different number of neutrons.
• Examples:
  • Carbon isotopes: C-12, C-13
• Relative Atomic Mass: Not a whole number due to different abundances of isotopes.

Summary

• Importance of understanding subatomic particles, their behavior under fields, and the concept of isotopes.
• Next: Part 2 of Lecture 1