- 
  
  published "The Proficience and Advancement of Learning" which contained a description of what would later be known as the scientific method.
- 
  
  wrote the first extensive list of elements containing 33 elements & distinguished between metals and non-metals
- 
  
  Developed a table of atomic weights & introduced letters to symbolize elements
- 
  
  Arranged the known elements in order of atomic weights & observed similarities between some elements
- 
  
  Lothar Meyer develops an early version of the periodic table, with 28 elements organized by valence
- 
  
  Dmitri Mendeleev produced a table based on atomic weights but arranged 'periodically' with elements with similar properties under each other. His Periodic Table included the 66 known elements organized by atomic weights.
- 
  
  Henry Moseley determined the atomic number of each of the elements and modified the 'Periodic Law'.
- 
  
  Glenn Seaborg synthesised transuranic elements (the elements after uranium in the periodic table)