Organizing the chemical elements into regularly recuring categories was a major step in the history of chemisty. The Russian chemist Mendeleev played an important role in creating the modern periodic table, and looking at how he got there provides some ideas for organizing, classifying, and analyzing large data sets.
First, the ideas around periodicity evolved over time. Scientists like Lavoisier, John Dalton, Prout, and Dobereiner contributed ideas around the elements and their proerties. Dobereiner discovered that certain groups of elements — eg strontium oxide had approximately the same weight as the average of the weights of barium oxide and calcium oxide.
SrO = CaO + BaO/2107 = (59 + 155)/2
The three element groups (Sr, Ca, Ba) are called triads. Others are Br, Cl, I (Bromium, Clorine, Iodine). The German scientist Johann Gmelin developed an arrangement of elements by triads as follows:
A key factor in developing the periodic table was good data. In 1860, Stanislao Cannizzaro published a paper with a consistent table of atomic weights of the then known elements for the Karlsruhe Conference, the first worldwide conference on chemisty. The availability of good data (and a predictive method for new elements) facilitated the arrangement by periods.Meneleev’s creation of the periodic table has traditionally been ascribed to having written element and atomic weight on small cards (like index cards) that he arranged on a desktop into periods. In 1869, he wrote a version of the periodic table on the back of an envelope, which he later refined.Looking at the process, having a physical manipulative (cards) and a physically written organization (diagram on the back of an envelope), facilitated discovering the order in the periodic table.At one point in my career I used to publish an annual data book with charts, data tables ‚and analysis around cloud services. To do it I created a prototype page and cut up each data table, graph, summary, and analysis section. We sat and reorganized the paper cutouts unti we found a pattern that told the story behind the data and uncovered the most insights. Something about shuffling paper and marking it up worked better than trying to do everything on the screen.
- The Periodic Table: It’s Story and Significance, Eric Scerri, Oxford University Press 2007.Eric Scerri’s book is a great summary of how the periodic table was created and what accelerated its development.
- Graphic Representations of the Periodic Table over 100 years, E.G. Mazurs, University of Alabama Press, 1974. Professor Mazur’s excellent collection of periodic table visualizations. Hard to find book — try a large university library.
- Wooden “manipulative” version created by Edward Mazurs.
- Chemical Heritage Museum Mazurs’ collection of periodic tables. (Philadelphia PA)
- Periodic Table Catalog. Online collection of visualizations of the periodic table (circular, lemniscate, etc) organized by date.
- All Periodic Tables Great resource site with pictures of various periodic tables.