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100
Democritus
The person who pathed the steps for the true Atomic Theory. His ideas where that the atoms where invisible and souldnt be broken down. The model was adopted around 450 BC, with Aristotle as the competitor. The model was adopted because though it didn't make sence at the time, it did in the long run. The experiment was threw sand, how they are so small and they cannot be broken down farther. -
100
Aristotle
Aristotle won the debate between whose atomic theory was better. Aristotles model made more sense. His model was the basic elements. Fire Water Earth Air. The answer that this model gave was that these elements have been made naturally. They cannot be created. The model was adopted near 450 BC. -
Period: to
John Dalton
Also know as the "Father of the Atomic Theory" He created theorums that scientists still use today. He proposed atomic theory, with spherical solid masses in motion. Atoms can't be made or destroyed. These theorums were adopted since it explained many a things. Many experiments are abd where to be done to explain why these theorums where adopted. -
Dalton's Atomic Theory
John Daltons theory is the basis and start of all Atomic Theorys. It states,
1. Elements are made up of tiny particles called atoms.
2. All atoms of a given element are identicle.
3. All atoms of a different element are different.
4. Atoms of one element can combine with atoms of one element and compose to make a new one.
5. Atoms can combine in chemical reactions but cannot be created nor destroyed. These theorums answered many questions. (For info about John Dalton, check out the time span) -
Period: to
Henri Becquerel
He discovered radiation along with Marie and Pierre Curie. -
Period: to
JJ Thomson
Discovered the electron. Used two experiments. Plum Pudding model and Cathode ray Tube experiment. -
Period: to
Marie and Pierre Curie
Marie and Pierre are a couple. Marie studied under Henri Becquerel, then discovered radiation. -
Period: to
Niels Bohr
Dedicated his time to physics, wining Nobel Peace Prizes. He introduced the idea of electrons orbiting around the nucleus. Chemical properties varying between sizes. -
Thomson's Cathode Ray Tube.
This experiment showed that every atom had a negative piece in it. Which is called the Electron. It was adopted since the cathode ray tube was beging to come out, it showed that every atom had a negative charge. It explained that everything has both positive and negative fields. This model is accurate. -
Period: to
James Chadwick
Dedicated his time researching many a things in science. Spenct time researching in Cambridge and Liverpool. Won a nobel peace prize. -
JJ Thomson's Plum Pudding Model
The plum pudding model founded the electrons. Basically it looked like a cookie. The electrons where surrounded by a soup of positive stuff to balance out the charges. Ernest Rutherford disproved this model in 1911, by using the gold-foil experiment. This experiment answered why the atoms stay together and how to calculate them. The gold-foil experimet disproved this model, -
Period: to
Robert Milikan
Helped develop quantum mechanics that would help develop quantum theories. 1927 Mulliken worked with Hund and as a result developed his molecular orbital theory, in which electrons are assigned to pieces that extend over the entire molecule. As a result, molecular orbital theory was also referred to as the Hund-Mulliken theory. -
Milikan's Oil Drop Experiment
This experiment was done to show and find the charge of an elctron. Discovered in 1909 by Robert Milikan. Its a fundamental physics constant and it accurates great value and importance. It explained how to calculate the charge of an electron. This evidence is accurate by performing many tests to prove the answer is correct. -
Bohr Planetary Model
Niels Bohr created the planetary model. It showed that the electron floated in orbit aroun the nucleus. Also showed how many protons there are to the atom. -
Quantum Model by Louis de Broglie
The Quantum Model shows how many of the electrons, protons and nutrons move around. Doesnt say the exact spot, nor stay in the exact spot but in fact moves around. This was adopted to test Bohr's experiment. It answered how fast can a wavelength travel threw an electron. This is accurate because it calulates the velocity and speed. -
Ernest Rutherford
He used the Photo Electric Gate, radiation an for finding the alpha radiation.He also did the Electron Cloud Model. This showed the very dense center called the nucleus. The nucleus ws surround by many electrons. This explained the nucleus, how the atom stays in shape. Gold foil experiment where the particles didnt go straight and bounced off of the gold foil. -
Chadwicks Discovery of the Nutron
James Chadwick discovered the nutron. This discovery was crucial for the discovery of the nucleur fission of the element uranium 235. This explains why elements can go threw heavier elements. This is accurate because it brought about the necluer collisions betwenn many elementd. This is adopted because it showed the balance between particles.
