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Period: 550 BCE to
Timespan of the Atomic Theory
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Period: 550 BCE to
Atomic Timeline
The Development of the Atomic Theory -
500 BCE
The Alchemists
The Alchemists created four elements. These elements consisted of earth, fire, air, and water. The Alchemists believed that these elements could be combines to create gold. This is significant to the atomic theory because it formed the basis of the Periodic table. -
500 BCE
The Alchemists
The Alchemists created 4 elements. These elements were fire, air, earth, and water. The believed that if they combined these elements, they could form gold. The Alchemists formed the basis of the periodic table. -
427 BCE
Plato
Plato was a greek philosopher who theorized that atoms were in the form of geometric forms. These shapes became known as "Platonic Solids" -
427 BCE
Plato
Plato theorized that atoms are in the form of geometric forms. These shapes were known as "Platonic Solids" -
400 BCE
Democritus
In around 400 BCE, Democritus, also known as "The Laughing Philosopher," stated that everything is composed of atoms. These atoms, will vary in terms of size and shape, and are indestructible. -
400 BCE
Democritus
In around 400 BCE, Democritus proposed a theory that states that everything is composed of atoms. Atoms are indestructible, and vary is size and shape. -
Robert Boyle
Robert Boyle proposed a theory which stated that elements are made of atoms (Or "corpuscles" as he liked to call them), that vary in size and type. These atoms are able to organize themselves into different groups, displaying different chemical substances -
Robert Boyle
Boyle proposed that elements are made of atoms ("Corpuscles" as he called them), which vary in size and shape. These atoms can be organized into different groups which represent different chemical substances -
Antoine Lavoisier
Antoine Lavoisier proved that matter cannot be created nor destroyed. This statement would be known as The Law of Conservation of Mass -
Antoine Lavoisier
Lavoisier proved that matter cannot be created nor destroyed. This statement would be known as The Law of Conservation of Mass. -
John Dalton
In 1803, Dalton's Atomic Theory was proposed. The theory stated that everything is composed of atoms, which are the building blocks of matter, and cannot be destroyed. -
John Dalton
Dalton proposed his atomic theory, stating that everything is composed of atoms, which are the building blocks of matter. Atoms cannot be destroyed, and vary is size. -
The Billiard Ball Model
Created by Dalton, this model is stating that there is nothing smaller than an atom, which are the building blocks of matter. -
Billiard Ball Model
Made by Dalton, the Billiard Ball Model shows an atom, and nothing else. This is indicating that there is nothing smaller than an atom. -
Amedeo Avagadro
Avagadro proposed Avagadro's law, which was that equal volumes of gas have equal numbers of molecules. Avagadro was also the first person to state that elements could exist as molecules, instead of atoms. -
Amedeo Avagadro
Proposed Avagadro's law. This law stated that equal volumes of gas have equal numbers of molecules. -
Dmitri Mendeleev
Dmitri Mendeleev was known for creating the periodic table. He sorted the elements on the table by atomic weight. Atomic numbers would not be discovered until after his death. -
Dmitri Mendeleev
Mendeleev sorted the elements by atomic weight into a table. This table would be the periodic table. -
JJ Thomson
Thomson discovered all atoms contain small subatomic particles. These particles were electrons, which were negatively charged. -
JJ Thomson
Thomson discovered that all atoms contain subatomic particles which are negatively charged. These particles became known as electrons. -
Pierre and Marie Curie
Pierre and Marie Curie was known for uncovering the 2 elements of polonium and radium, both of which are extremely radioactive. Because of the radiation, the discovered radioactivity. -
Pierre and Marie Curie
The Curies uncovered 2 highly radioactive elements, known as polonium and radium. As a result of the exposure to radiation, the discovered radioactivity. -
Plum Pudding Model
The Plum Pudding model was a model by JJ Thomson in 1904. The model shows negatively charged electrons inside a positive charged ball. -
Plum Pudding Model
The Plum Pudding model was created by JJ Thomson. It shows negatively charged electrons inside a positively charged ball. -
Albert Einstein
Albert Einstein, in 1905, proved the existence of atoms mathematically. -
Albert Einstein
Einstein was able to mathematically prove the existence of atoms in 1905. -
Robert Millikan
Robert Millikan, in 1909, discovered the charge of an electron, This fundamental charge that was discovered was huge for the atomic theory. -
Robert Millikan
Millikan discovered the charge of an electron in 1909 -
Ernest Rutherford
Ernest Rutherford was known for discovering that an atom has an abundance of space, as well as a positively charged nucleus. -
Ernest Rutherford
Rutherford discovered that the atom has an abundance of empty space, and is composed of a positively charged nucleus. -
Neils Bohr
Bohr proposed a theory revolving around the hydrogen atom. The theory said that electrons move around the nucleus in an orbit. If an electron goes to a lower energy orbit, the difference is sent via radiation. -
Solar System Model
The Solar System model shows a nucleus in the center, with electrons orbiting around the nucleus. -
Neils Bohr
Bohr proposed a theory for the hydrogen atom, which said that electrons move around a nucleus in an orbit. When electrons transfer to a lower orbit, the difference is sent by radiation. -
Solar System Model
This model shows the nucleus, made up of the protons and neutrons, and electrons orbiting around. -
Henry G. J. Mosely
Mosely concluded that the atomic number of an element is equivalent to the number of positive charges within the nucleus. This discovery would reshape the periodic table, where the elements were in order of atomic numbers rather than atomic weight. -
Henry G. J. Mosely
Mosely concluded that the atomic number of an element is equivalent to the number of positive charges in the nucleus. -
Erwin Schrödinger
Schrodinger, in 1926, used equations to figure out the likelihood in of an electron being in a certain position. -
Electron Cloud Model
The Electron Cloud model was created by Schrödinger, and showed a nucleus in the middle, with an electron cloud representing the orbit of the electron. -
Erwin Schrödinger
Schrödinger used equations to figure out the likelihood of an electron being in a certain position. He also created the Electron Cloud Model. -
Electron Cloud Model
Created by Erwin Schrödinger, this model shows a nucleus in a center, and an electron cloud surrounding the nucleus, indicating the electron orbit -
Werner Heisenberg
Werner Heisenberg was a German Physicist, who discovered the Uncertainty Principle. This principle stated that a particle's momentum and exact place is unknown. -
Werner Heisenberg
Heisenberg was a German Physicist, and discovered the uncertainty principle. This principle stated that a particle's momentum and exact place is unknown. -
James Chadwick
Chadwick discovered the neutron in 1932, a neutrally charged particle that occupies the atomic nucleus. -
James Chadwick
Chadwick discovered the neutron, a neutrally charged particle that occupies the atomic nucleus,