History of Atomic Theory

Democritus

100

5th century bc ( Incorrect in title, thats the earliest it would let us put it ) First one to think of matter as a sum of many smaller pieces

John Dalton

Jan 1, 1766

Proposed an atomic theory in 1803 First one to actually give a name and explanation to what made up matter Solid spherical Atoms Little do they know, he actually named the atom after his best friend Adam!!!

Antoine Lavoisier

Sep 30, 1778

Identified and named Oxegen and Hydrogen MAde the first full list of elements

Joseph Louis Proust

Sep 30, 1794

Proposed the Law of Constant Composition, which states that the ratio by mass of the elements in a chemical compound is always the same.

Michal Faraday

Jan 1, 1832

Studied the effects of “electrolysis” ( the splitting of molecules using electricity )in 1832. Observed the effects of the ion without actually discovering it Invented Benzene Developed the laws of electrolysis Don’t ask us to explain the meme, we don’t get it either.

Henri Becquerel

Jan 1, 1896

Studdied the effect of X-rays Discovered what would later be named radiation by the Curies Discovered certain particles spontainiously decomposed and give off radiation.

J.J. Thomson

Sep 30, 1897

Discovered the electron Suggested the atom might be a sphere with a positive charge and have negativley charged electrons orbiting it.

Marie & Pierre Curie

Sep 30, 1898

Discovered Radium Experimented with radiation and the properties of radioactive elements

Max Planck

Sep 30, 1900

Further studdied radiation. Discovered the relationship between energy and radiation

Robert Millikan

Sep 30, 1909

Conducted an expiriment with oil drops and discovered the mass of the electron and its charge. Maths: e= 1.062 x 10 -19 coulomb
m= 9.11 x 10 -28 gram

Ernest Rutherford

Sep 30, 1911

Theorized that most of an atoms mass and charge are in a nucleus 1/10'000 the size of the atom itseld i.e. the proton.

Neils Bohr

Sep 30, 1913

Created the modern atom model
this is why we call them Bhors models

Albert Einstein

Nov 1, 1950

Developed the theory of realativity. E=mc2 helped calculate the mass energy equivalence

James Chadwick

Sep 30, 2014

Discovered the neutron, a neutrally charged partical Was renound for his creativity in naming particals

Aristotle

Mar 2, 2022

Philosipher aroung 380 B.C (again with the Website not working with BC). Aristotle believed that regardless of the number of times you cut a form of matter in half, you would always have a smaller piece of that matter.