section_path: History/Chemical definitions/Antoine Lavoisier, Jöns Jacob Berzelius, and Dmitri Mendeleev
section_name: Antoine Lavoisier, Jöns Jacob Berzelius, and Dmitri Mendeleev
paragraph_text: Antoine Lavoisier, Jöns Jacob Berzelius, and Dmitri Mendeleev
  
  The first modern list of elements was given in Antoine Lavoisier 's 1789 Elements of Chemistry, which contained 33 elements, including light and caloric. By 1818, Jöns Jacob Berzelius had determined atomic weights for 45 of the 49 then-accepted elements. Dmitri Mendeleev had 63 elements in his periodic table of 1869.
  
  From Boyle until the early 20th century, an element was defined as a pure substance that cannot be decomposed into any simpler substance. That is, an element cannot be transformed into other elements by chemical processes. Elements at the time were generally distinguished by their atomic weights, a property measurable with fair accuracy by available analytical techniques.