PUBLIC MARKS with tags interactive & "periodic table"

In the 19th century Dmitri Mendeleev organized the known elements by their characteristics and atomic weights. His creation evolved into what we now call the periodic table. We use it regularly, but what would it be like to construct that model from scratch? What if you had to group elements by their characteristics and place them on a table close to the other elements in their group, while at the same time logically arranging the atomic weights? What decisions would you make? What would it be like... to be Mendeleev?