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Democritus starts the atomic theory (THIS EVEN HAPPENED IN BC)
(THIS EVENT HAPPENED IN BC) Democritus begins to philosiphize about the existence of atoms. He believed that everything in the universe is made up of small spheres called atoms. Although no one really believed him, He still is considered the father of the Atomic Structure. -
Lavosier tests oxygen in combustion
Lavosier tests for oxygen's role in combustion and found that oxygen is necessary for things to catch on fire. He also discovered and named Oxygen and Hydrogen. -
John Dalton proposes "Atomic Theory"
John Dalton proposed his "Atomic Theory". This theory states that anything that has mass must be made up of small, spherical particles called "atoms". -
J.J. Thomson learrns more of the electron
J.J. Thompson discovered the charge to mass ratio of the electron. This number is 1.759 x 10^8 coulombs/gram. He also mentored Bohr and Rutherford. -
Marie Curie discovers radioactivity
Marie Curie studied the decay process of uranium and plorium. She later called this process "Radioactivity". She also worked with her husband to discover Radium and Polonium. -
Max Planck discovers "Quanta"
Max Planck Discovered "quanta". Quanta are short discrete burts of energy. He used quanta to explain how iron pokers glow red and white after they are used. -
Albert Einstein coins E=MC^2
Albert Einstein coins his famous equation E=MC^2. This formula means that the energy released in a reaction is equivelent to the mass of the object times the speed of light squared. -
Robert Millikan and his Oil drop experiment
Robert Millikan used his Oil Drop experiment to test the mass and charge of an electron, as only the ratio had been determined so far. He found that the mass of the electron to be 9.11 x 10^-28 gram and the charge of the electron to be 1.602 x 10 -19 coulomb. -
Ernest Rutherford
Ernest Rutherford discovered that atoms have nuclei which are made up of protons (The neutron wasn't discovered yet) and that electrons orbit the nucleus. He discovered this by firing alpha particles at a sheet of gold. When some of them bounced back at him, he decided that this must mean that atoms must have a dense center as well as electrons orbiting this dense center. He called this center the nucleus. -
James Chadwick discovers the Neutron
James Chadwick discovers the neutron. He did this by firing alpha particles through a sheet of berylium and a sheet of parafin. When some particles bounced back at him, he found that atoms have a solid more dense center with less dence particles surrounding it, rather than a circle that is positively charged full of negatively charged pockets. -
Niels Bohr redesigns the atomic model
Niels Bohr redesigned the atomic model. The new model arranged the electrons in rings around the atom, rather than in a clouds of orbits around the Nucleus. -
Louis de Broglie Discovers more about electron's movement
Louis De Broglie discovered that electrons move around the nucleus in wave-like motions, rather than straight lines. This discovery further supported the findings of Albert Einstein. -
Heisenberg writes the theory of indeterminancy
Heisenberg wrote the theory of indeterimnancy. This theory states that the more you know about an objects momentum, the less you know about an objects position and vice versa. This mainly portains to electrons in the atomic theory. -
Schrodinger revamps electrons
Schrodinger revamps the electronic model by introducing wave mechanics to electrons. This added a new mathmatical model to the atom that previously wasn't there. He did this by viewing electrons as one continuous clouds which constantly is moving.