Dufour’s 3D Periodic Table
Dufour’s 3D periodic table also called Dufour’s periodic tree is one of alternatives to the common representation of periodic table. In Dufour’s periodic tree, the s-block elements are located at the trunk of the tree, except for helium which has the smallest branch at the top. Other elements are located at hollow hexagons (disk-like shapes) around the trunk viewed as the branches. Each row of the p-block elements has its own specific disk, as it is for the d-block and f-block elements where disks belonging to a same block have a same size but sizes of disks increase from the p-block elements to the d-block elements to the f-block elements.