The periodic table is an icon. But chemists still can't agree on how to arrange it
Building the Periodic Table Block by Block | HowStuffWorks
Simply Education HK - Elements in the Periodic Table are not only classified into Groups and Periods, but also Blocks. This is explained by the detailed electronic configuration you are going to
Reading the Periodic Table
1.4: Block classification of the periodic table and elements - Chemistry LibreTexts