Lecture Notes: Upcoming Assignments, Exams, and Quantum Numbers

Overview

• Homework & Assignments:
  • First part of Chapter 1 due Thursday: Light, wavelength, frequency, Bohr model, energy
  • Second part of Chapter 6 (quantum numbers, orbitals, electron configurations) with Chapter 7 (periodic trends) due next Tuesday
• Exam:
  • Exam 3 on next Tuesday covering Chapters 5-7

Test Corrections

• Grading taking longer, feedback available by Thursday

Quantum Numbers & Atomic Orbitals

• Principal Quantum Number (n):
  • Indicates size of the orbital
  • Relates to row on the periodic table (e.g., 6p orbital in 6th row)
• Quantum Number (L):
  • Indicates orbital type/shape (s, p, d, f)
  • Example shapes:
    • s = sphere
    • p = dumbbell (Px, Py, Pz)
    • d = four-leaf clover
    • f = complex

Electron Configurations

• Exceptions to Usual Configurations:
  • Groups 6 & 11 anomalies
  • Chromium: Exhibits 4s1 3d5 instead of 4s2 3d4
  • Copper: Exhibits 4s1 3d10 instead of 4s2 3d9

Nodes & Orbital Energies

• Nodes: Areas within an orbital where electrons cannot exist
  • Radial nodes (n-L-1) and angular nodes (L)
• Energy levels: Changes with electron number and orbital shapes

Electron Configurations for Ions

• Anions: Gain electrons, reach noble gas configuration
• Cations: Remove highest n value electrons first (s before d)

Periodic Trends

• Effective Nuclear Charge (Z_eff):
  • Charge felt by valence electrons
  • Increases across a period, reduces down a group
• Atomic Size:
  • Increases down and to the left
• Ionization Energy:
  • Increases to the right and up
• Electron Affinity:
  • Energy change when adding an electron, follows similar trend to ionization energy
• Electronegativity:
  • Ability of an atom to attract electrons in a bond
  • Increases to the right and up
• Ionic Size:
  • Cations are smaller with higher positive charge
  • Anions are larger with higher negative charge

Review Plans

• Review Chapters 5-7 for upcoming exam on Tuesday
• Office hours for additional questions