Dimitri Mendeleev
Pasted GraphicDimitri Mendeleev was a Russian Chemistry Teacher who was searching for a way to help his students categorize the elements to better remember them. In 1869 he published his first periodic table in his chemistry textbook. He arranged the elements in specific horizontal rows and vertical columns according to their physical properties and in order of increasing mass. Later they were slightly rearranged by increasing atomic number. Since all the elements had not yet been discovered, Mendeleev had the good sense to leave spaces in his chart and even predicted the masses of elements that would later fit into those "holes."

  1. A very interesting, interactive Periodic Table which has great images of all the orbital shapes.
  2. A Periodic Table loaded with information about each element.
  3. A very visual Periodic Table also loaded with information.
  4. One more interactive Periodic Table.
  5. Try this Periodic Table − you can see the bright line emission spectrum for each element.
  6. A website that lists ionization energies of each element.