19th century atomic theory and periodic table

• John Dalton's atomic theory

  Elements consist of indivisible atoms. Atoms of the same element are identical and atoms of different elements differ.
• Development of the periodic table by Dmitri Mendeleev


  Organized elements by increasing atomic mass. Predicted properties of undiscovered elements. Highlighted periodic trends in properties
• Discovery of new elements

  Advances in chemistry and spectroscopy led to identification of noble gases. Separation of elements