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440
Democritus Speculated About Atoms.
Around 440B.C. Decocritus theorized that atoms made up everything, were in constant motion, can not be destroyed, and there is an infinite number of atoms of different size and shape. -
Robert Boyle Invents His Law
Robert Boyle concludes that pressure and volume exhist in an inverse relationship when temperature and the number of molecules are help constant. I.E. PV=k -
Antoine Lavoiser Writes First List of Elements.
Antoine Lavoiser made numerous contributions to chemistry. He discovered and named oxygen (1778), and hydrogen (1783). Also, he predicted the existance of silicon (1787) established that sulfer was an element rather than a compound (1777),proved the conservation of mass during a chemical reaction (1774), and wrote the first list of elements. -
John Dalton Proposes His Atomic Theory
John Dalton proposed his atomic theory stating that 1. elements are made of atoms, 2. atoms of an element are identical, but differ from atoms from other emelents, 3. atoms cant be broken down or destroyed, 4. atoms combine to form chemical compounds, and 5. atoms are combined, separated, or rearranged during a chemical reaction. This causes other chemists to start looking more closely at the atom. -
Dmitri Mendeleev Creates the Periodic Table
Mendeleev's periodic table listed the elements according to their atomic weights and also their number of valence electrons. He was even able to predict 8 more elements that were not discovered at that time. Today, he is known as the father of the periodic table. -
Eugen Goldstien Discovers the Proton
Around 1886 Eugen Goldsten discovered the proton using cathode ray tubes. However the charge of this particle is still unknown at this point in time. -
J.J. Thomson Discovers Electrons
Using cathode ray tubes J.J. Thomson discovered electrons begining the race to see who can fully explore the atom first. -
Robert Millikan Determines the Charge of Electrons
In 1909 Robert Millikan discovered that a single electron carries a negative charge by measuring the course made by charged water droplets through a magnetic field. -
Ernest Rutherford Discoveres Nucleus
Ernest Rutherford discovered the nucleus of the atom in 1911 with his gold foil experiment. This discovery caused other scientists to start looking into the nucleus to learn more about it. -
Niels Bohr Issues his Theory of Electrons
Niels Bohr issued his theory of electrons stating that electrons orbit around the nucleus around a track, but are able to jump to anoher track. -
Henry Mosely Invents the Atomic Number
By using x-rays, Henry Mosely came up with the system for atomic numbers. Before this, there was no constant way to list the elements. -
Max Planck and Quantum Mechanics
In the 1902's Max Planck was a pioneer in theoretical physics. He developed quantum mechanics, or how subatomic particles move. -
Erwin Schrodinger and Quantum Mechanics
Shortly after the development of quantum mechanics Schrodinger developed his own quantum theory of how particles move. In addition he published his theory of wave mechanics, and made numerous other contributuions to the field. -
Sir James Chadwick Discovers the Nuetron
In 1932, by looking at gamma rays, Sir James Chadwick discovered the neutron.
