Class Lecture Notes for CHEM 21A at El Camino Community College

The following documents are lecture materials for Chapter 3 that will be used in class. Please download them and bring them to class.


  • Chapter 3, section 3.1 - The Periodic Law and Table
  • Chapter 3, section 3.2 - Electronic Arrangements in Atoms
  • Chapter 3, section 3.3 - Valence Shell and Chemical Properties
  • Chapter 3, section 3.4 - Electronic Configurations
  • Chapter 3, section 3.5 - Another Look at the Periodic Table
  • Chapter 3, section 3.6 - Property Trends within the Periodic Table