Using the Diagonal Rule to Write Electron Configurations

In general chemistry classes the diagonal rule is often taught as a (fairly) easy way to write electron configurations for the elements. It works very well for the first 20 elements on the Periodic Table and reasonable well for elements after that (see links below for exceptions). I prefer to use the only the Periodic Table (   • Writing Electron Configurations Using Only...  ) but the Diagonal Rule is a useful tool. More Videos on Electron Configurations Introduction to Electron Configs:    • Introduction to Electron Configurations   Configs using only the Periodic Table:    • Writing Electron Configurations Using Only...   Configs for Ions:    • How to Write the Electron Configuration fo...   Important Exceptions to the Rule:    • Electron Configuration Exceptions Examples...  : Abbreviated Configurations:    • Writing Condensed/Abbreviated Electron Con...   --Diagrams in the Video-- First Diagonal Diagram: https://commons.wikimedia.org/wiki/Fi... https://commons.wikimedia.org/wiki/Fi...]. Second Diagonal Rule Diagram: https://commons.wikimedia.org/wiki/Fi... https://commons.wikimedia.org/wiki/Fi...].