1.1 What is Chemistry?

6.1. History of the Periodic Table http://www.ck12.org

Lesson Summary

• The early versions of the periodic table included approximately 60 known elements, while our current version
  includes 118.


• An early version of the periodic table was first published by Julius Lothar Meyer in 1864, where he used the
  concept of valence to group similar elements together.


• In 1865, Newlands described a periodic pattern in the properties of the elements that he referred to as the Law
  of Octaves. This anticipated later developments in our understanding of the periodic law.


• Between 1869 and 1871, Russian chemist Dmitri Mendeleev systematically arranged 60 elements based on
  increasing atomic weight.


• Mendeleev’s table became widely accepted, primarily because he predicted the characteristics and placement
  of elements which were yet to be discovered.


• One of the major developments that allowed for what became known as the periodic table was the idea of
  atomic mass, which is attributed to John Dalton.


• Characteristic properties of the elements could be related to atomic mass and atomic number.


• Ordering the elements by atomic number instead of atomic mass cleared up some of the discrepancies found
  in older periodic tables and provided the basis for our current table of the elements.

Lesson Review Questions

1. Create a timeline that shows the contributions from the various scientists which led to the evolution of the
   periodic table.


2. What were some of the limitations of the early versions of the periodic table?


3. What were some aspects of Mendeleev’s table that helped convince the scientific community to adopt its use?


4. How was Mendeleev’s table arranged? What was systematic about it?


5. What predictions did Mendeleev make with his table that were later confirmed?


6. What contributions did Moseley make to the modern periodic table?


7. The periodic table has evolved over time. Do you suppose it is a completed table at this point? In other words,
   will it evolve further in the future?

Further Reading / Supplemental Links

• Barber, R. C., Karol, P. J., Nakahara, H., Vardaci, E., Vogt, E. W. (2011). Discovery of the elements with
  atomic numbers greater than or equal to 113 (IUPAC Technical Report). Pure and Applied Chemistry, 83(7),
  1485 - 1498.


• Bonifácio, V. D. B. (2012). QR-Coded Audio Periodic Table of the Elements: A Mobile-Learning Tool.
  Journal of Chemical Education. doi: 10.1021/ed200541e


• Hsu, D. D. (2012). Chemicool Dictionary, from http://www.chemicool.com/dictionary.html


• Gorin, G. (1996). Mendeleev and Moseley: The Principal Discoverers of the Periodic Law. Journal of
  Chemical Education, 73(6), 490. doi: 10.1021/ed073p490


• Trimble, R. F. (1981). Mendeleev’s discovery of the periodic law. Journal of Chemical Education, 58(1), 28.
  doi: 10.1021/ed058p28


• van Spronsen, J. W. (1969). The priority conflict between Mendeleev and Meyer. Journal of Chemical
  Education, 46(3), 136. doi: 10.1021/ed046p136