-
440 BCE
Plato
He developed wide-ranging philosophical system, known as Platonism, and propsed that a 5th atomic type has to exist. britannica.com/summary/Plato -
400 BCE
Democritus
He was the first person to describe invisible “atoms” as the basis of all matter. britannica.com/summary/Democritus -
Robert Boyle
Started creating many chemical expirements, and defied the idea of an element. britanica.com/summary/Robert-Boyle -
Antone Lavoisier
He formulated the principle of the conservation of mass. britannica.com/summary/Antoine-Lavoisier -
The Alchemists
The alchemists contributed to the Atomic theory by laying down the foundation of the Periodic Table of Elements prezi.com/t50cihtay12m/alchemy-and-its-contributions-to-the-atomic-theory -
John Dalton
Created Dalton’s atomic theory. britannica.com/biography/John-Dalton/Atomic-theory -
Billiard Ball Model
Was created by John Dalton. It showed atoms as hard, solid spheres. Similar to billiard balls therefore he used these balls as atom models. ck12.org/chemistry/daltons-atomic-theory/lesson -
Amedeo Avogadro
Showed that under controlled conditions of temperature and pressure, equal volume of gases contain an equal number of molecules (Avogadro Law). britannica.com/biography/Amedeo-Avogadro -
Dmitri Mendeleev
He created the periodic table by arranging the elements ascending order of atomic wieght, and he created the Mendeleev theory. britannica.com/summary/Dmittri-Mendeleev -
JJ Thomson
He discovered electrons. britannica.com/summary/J-J-Tomson -
Pierre and Marie Curie
They theorized that uranium rays come from the elements atomic structure. britannica.com/summary/Marie-Сurie -
Plum Pudding Model
This model represents a step in the development of the atomic theory, and it helped scientists understand that atoms are composed of smaller units of matter. universetoday.com/38326/plum-pudding-model/ -
Albert Einstein
He published an article on the photoelectric effect in which he demonstrated the particle nature of light. britannica.com/summary/Albert-Einstien -
Robert Millikan
He studied the elementary electronic charge and the photoelectric effect. britannica.com/biography/RObert-Millikan -
Ernest Rutherford
He found that the atom consists mostly of empty space with its mass concentrated in the nucleus. britannica.com/summary/Ernest-Rutherford -
Neils Bohr
He was the first to apply the quantum theory to atomic and molecular structure, and his concept of the atomic nucleus helped with the understanding nuclear fission. britannica.com/summary/Neils-Bohr -
Solar System Model
Created my Niels Bohr. The model is a diagram of a atom consisting of protons, neutrons, and electrons. thehistoryoftheatomicmodel.weebly.com -
Henry G. J. Mosely
He stablished the relationship between atomic number and the charge of the atomic nucleus. britannica.com/biography/Henry-Moseley -
Erwin Schrodinger
He made fundamental contributions to quantum mechanics. britannica.com/summary/Erwin-Schrodinger -
Werner Heisenberg
He solved the problem of how to account for stationary discrete energy states of an anharmonic oscillator, which launched the development of quantum mechanics. britannica.com/summary/Werner-Heisenberg -
Electron Cloud Model
This model is of an atom that is made up of small but massive nucleus surrounded by a cloud of rapidly moving electrons, and it says we can’t exactly know at any given time where an electron is. Though, more than likely to be in specific areas. nuclear-power.com/nuclear-power/reactor-physics -
James Chadwick
He discovered nuetrons. britannica.com/biography/James-Chadwick