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Democritus's theory
Democritus theorized that atoms veried in size and were indivisible, he also theorized that there was a small amount of space between each atom, and that atoms alwayse will move.
Important to this theory, is the idea that each atom was specific to what it was inside of, such as a cheese atom in cheese, or glass atom in glass. more information can be found here: Wiki http://www.youtube.com/watch?v=thnDxFdkzZs -
Antoin Lavoisier
The discoverer of hydrodgen, this french scientist was responsible for discovering that hhydrogen and oxygen created water, and was also responsible for disproving the idea that air, which was thought to be an element was actually a mixture of gases. Sources: http://www.youtube.com/watch?v=ZgmGxN66rTQ -
Plum pudding atomic model
Proposed by J.J Thompson, the plum pudding model dictates that atoms remain in place around the centre of an atom, comparable to the fruit in a plum pudding. Source: http://www.universetoday.com/38326/plum-pudding-model/ -
John Dalton
John Dalton proposed that atoms were made up of small particles that were indivisible, he called these atoms, he also proposed that atoms of each element are identacle in size and mass, and that atoms cannot be created or destroyed. Source: http://www.youtube.com/watch?v=sDoH5fPTOfo -
Daltoms atomic theory
Dalton's theory was this:
1) All matter is made of atoms. Atoms are indivisible and indestructible.
2) All atoms of a given element are identical in mass and properties
3) Compounds are formed by a combination of two or more different kinds of atoms.
4) A chemical reaction is a rearrangement of atoms. -
Dimitri mendeleev
Responsible for arranging elements into 7 groups with similar properties, known as periodic law. Source: atomictimeline.net/index.php -
J.J Thompson
J.J Thompson found, through the use of cathoid ray tubes that atoms contained tiny negatively charged particles. He found this by applying positivly and negativley charged sources on either end, and saw tat the ray had bet towards the positivly charged source on the opposite end, meaning, that the presence of negatively charged particles could be confirmed. he called these corpuscles, but these were later renamed, Electrons. More information: http://www.youtube.com/watch?v=Rb6MguN0Uj4 -
Cathode Ray tube
A cathode ray tube is a kind of tube from wich all air has been evacuated, it also includes 2 paices of metal, wich when electrified, emit an invisible beam that flashes when it strikes the end of the tube which has been coated with a specific agent. In order to prove the existence of electrons, J.J Thompson applied a positive power source to one side and a negative to the other, resulting in the beam bending towards the negative side, therefore proving the existence of neutrons. -
The Gold foil experiment
A scientist named Ernest Rutherford conducted an expeirement involving gold foil, This experiment would soon disprove the then current theory, called the plum pudding theory.
This experiment involved shooting atoms at high speeds through a paice of gold foil, Rutherford soon found that some of the atoms going through the foil bounced back, leading him to soon theorize about the concept of a nucleus. Sources: http://www.youtube.com/watch?v=dNp-vP17asI -
Rutherford model
The rutherford model is is most comparable to the planetary model, it is an update to the plum cake model. Source: http://en.wikipedia.org/wiki/Rutherford_model -
Robert Millikan
Robert millikan is responsible for creating the equation for finding the electric charge of an electron, this was done via an experiment commonly known as the oil drop experiment. This experiment involves miniscule drops of oil, and electricity, the theory being that negatively charged electrons would repel themselves from positively charged surfaces, and be attracted to negetively charged surfaces.
source: http://www.youtube.com/watch?v=2HhaQtvICe8 -
Bohr planetary model
Neils Bohr proposed that all atoms are made up of protons and neutrons in the centre, as well as electrons orbiting in what he called energy levels. Source: http://csep10.phys.utk.edu/astr162/lect/light/bohr.html -
Henry Moseley
Using X-ray tubes, he detrmined the charges on the nuclei of most atoms. His works directly influenced the periodic table. -
Electron cloud model
Similar to the planetary model, this model, shows electrons as clouds, dipicting their estimated paths. this was created when the planetary model was considered obsolete. Sources: http://simple.wikipedia.org/wiki/Electron_cloud http://www.universetoday.com/38282/electron-cloud-model/ -
Erwin Scrodinger
Erwin Schrodinger is responsible for developing an equation that describes the motions and energies of electrons in orbit around a nucleus. He proposed that electrons can only occupy specific orbits around a nucleus. Source : www.ask.com/answers/21649912/which-contributions-did-erwin-schr-dinger-make-to-modern-atomic-theory -
Quantum mechanical model
The Quantum mechanical model is a mathmaticle equasion used by scientists to predict where an electron might be, this equaltion considers many variables and is very complex. Source: http://www.youtube.com/watch?v=cKzh5yeQGjA -
Quantum mechanical model
Proposed by Max Planck, and extended on by Albert Einstein. This theory states that electromagnetic radiation, such as light, has characteristics of both a wave, and a stream of power. Source: http://www.sparknotes.com/testprep/books/sat2/chemistry/chapter4section4.rhtml -
James Chadwik
Responsible for the discovery of the neutron, he fired alpha particles at a byrillium rod, and found that the irradiated waaves contained a neutral particle, the neutron. Source: http://www.youtube.com/watch?v=_7DAlvRI1M4 -
Ernest Rutherford
He is Most well known for his gold foil experiment, and the creation of the planetary model of the atom. source: http://www.youtube.com/watch?v=Xb9KnwadI6Y -
Neils Bohr
Developer of the Bohr Rutherford model, Neils Bohr was a Danish scientist who made many mojor contributions to our understanding of Atomic structure, and Quantum theory. Source: http://en.wikipedia.org/wiki/Niels_Bohr
