In 1789 Antoine Lavoisier published his Traité Élémentaire de Chimie, or Elements of Chemistry. It became the same for chemistry as Newton's Principia of 1687 had been for physics.
Lavoisier is famous for the Law of Conservation of Mass 1783, which is similar to the first law of thermodynamics, in that the mass of a closed system stays the same over time. As I pointed out in another post, he also found oxygen and used this finding to bring down the flogiston theory.
John Dalton (1746-1844), born into a Quaker family and initially prohibited by law as a dissenter to study at English Universities, laid down an atomic theory around 1800 with the following main points:
The atoms of a given element are different from those of any other element. The atoms of different elements can be distinguished from one another by their respective relative atomic weights.
All atoms of a given element are identical.
Atoms of one element can combine with atoms of other elements to form chemical compounds.
A chemical reaction only changes the way atoms are grouped together. The atom is indivisible.
Dalton did not like the simplified notation of Jöns Jacob Berzelius (1779-1848) that became popular. Berzelius became a member of the Royal Swedish Academy of Sciences in Sweden 1808 and awakened it after a dormant romanticism period in Sweden. He participated with the discovery of several elements.
In 1828 Friedrich Wöhler (1800-1882), a German chemist, accidentally synthesized the organic compound urea for the first time. It was a landmark discovery since it linked chemistry with the biological world and disproved and undermined the Vital Force Theory. He also found several elements.
The creation of the periodic table of elements in 1869 is generally credited to a Russian by the name Dimitry Mendeleev (1834-1907). The table illustrated recurring trends in the properties of elements.
In 1896 Henri Becquerel (1852-1908) discovered that certain elements emit radiation on their own accord.
Ernest Rutherford (1871-1937), a New Zeeland chemist and physicist, became known as the "father of nuclear physics". He discovered in 1911 that the bulk of the matter in an atom is concentrated in a positive core with the electrons moving around it. An unstable configuration, because of the repelling charges.
Data from Wikipedia