1869 (Mendeleev’s table) / Europe
The periodic table becomes a tool for prediction
Mendeleev arranged elements by atomic weight and chemical properties, leaving gaps for missing elements. Meyer and other chemists also contributed to the periodic system.
The story
The 1869 table organized recurring chemical properties. Mendeleev left places for undiscovered elements and developed testable predictions in subsequent work. Meyer, Newlands and others pursued related patterns. Today’s table uses atomic number, a basis clarified through later research on atomic structure; it should not be projected unchanged onto the 1869 table.
Connections and context
Patterns could reveal missing knowledge as well as classify known substances. New elements, precise measurements and atomic research repeatedly tested and revised the table.
Dates and precision
1869 (Mendeleev’s table) Documented date
Positioned by the documented year, month or day. Missing precision is not inferred.
Representative map location
Saint Petersburg
The marker represents Mendeleev’s principal setting; related research took place across Europe.
Representative coordinates · 59.9343°, 30.3351°
A marker identifies one representative place, such as a manuscript collection, laboratory or observing site. It does not mean the work happened only there, or assign a shared discovery to one country.
Bibliography
- Royal Society of Chemistry: Development of the periodic table
- Periodic table history (American Chemical Society)
- The evolution of the periodic table (Royal Society of Chemistry)
References are listed as plain bibliography titles. They support particular facts or context; a reference does not certify every interpretation in a story.