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100
Democritus
460-370 B.C.
Ancient Greek philospher that discovered a particle of matter that cannot be divided. He called it an atom and said that they are small hard particles that are made of 1 single material. No one believed him because back then, it was impossible to know that. -
100
Aristotle
350 B.C.
Ancient Greek philosopher that believes that there are 5 elements: Earth, Wind, Fire, Water, Ether. His theory became a common belief. -
100
Aristotle Atomic Theory
Here is the atomic motel of Aristotle -
100
Democritus
This is the atomic motel of Democtritus -
Period: 100 to
Atomic Theory
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John Dalton
Scientists from Cambridge, England. He created the Billard Ball Model and came up with four new ideas about the atom. 1.Everything is made up of atoms. Atoms are small particles that cannot be divided
2. Atoms of the same element are exactly alike. Atoms of a different element are different
3. Atoms join with each other to form new substances
4. In chemical reaction, atoms are combined, seperated, and changed -
Dalton atomic model
This is the atomic model of Dalton -
Sir. William Crookes
He created a sealed glass tube connected to a battery. That allowed Crookes to see the pathways of electrons -
Crookes atomic model
The atomic model of Crookes -
Dmitri Mendeleev
He organized the elements. This became to basis for the modern periodic table. -
Mendeleev atomic model
This is the atomic model of Mendeleev -
J.J. Thomson
He created an experiment that involved holding a magnet which would direct a light beam. The magnet bent the ray towards the positive side of the magnet. He decided that the ray must have a negative charge. He created a model known as the Plum Pudding Model -
Thomson's atomic model
This is the atomic model of Thomson -
Ernest Rutherford
Created a experiment that made particles go through a piece of gold foil with no resistence. He created a new model that involved dense, positive nucleus surrounded by negative electrons -
Rutherford's atomic model
This is the atomic model of Rutherford -
Niels Bohr
He created a model of an atom that had the electrons moving around the nucleus on designated paths. This is still used today to demonstrate the shape of the atom. -
Bohr
This is the atomic model of Bohr -
H.G.J. Moseley
He discovered using x-rays the charge of the nucleus. He used his technique on many elements. He determined that the atomic number of an element is the number of protons in the nucleus of an atom. -
Moseley atomic model
This is the atomic model of Meseley -
Werner Heisenberg
He discovered that electrons do not move in neat orbits. He said all electrons contain photons and that they change their movement. This is known as the Uncertainty principle -
Heisenberg atomic model
This is the atomic model of Heisenburg -
Erwin Schrödinger
Erwin Schrödinger devised a way to predict where the electron is most likely to be at a given time. The area the electron is traveling in is known as the electron cloud, the most dense section of the cloud is where the electron is most likely to be -
Schrödinger atomic model
This is the atomic model of Schrödinger -
Chadwick
Chadwick discovered neutrons, and added them onto the atomic model -
Chadwick atomic model
This is the atomic model of Chadwick
