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Period: to
Atomic Theory
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John Dalton
He was the pioneer in testingwhat happens to liquids when turned into gas. He also was the first to develop atomic weight. There were only 6 elements on the table at first which were hydrogen, oxygen, nitrogen, carbon, sulfur, and phosphorus. -
American Independence Declared
The United States of America claims independence from Great Britain -
Joseph John Thomson
He discovered electrons and isotopes as his most famous work and also created the mass spectrometer. He discovered isotopes while trying to explain the decay of certain radioactive elements. -
Max Planck
He created what is known as Planck's constant which explained the pattern of light intensity. many other scientists used his constant to prove other data for atomic theory. -
Civil War
The Confederate States declare to surrender and join the Union -
Robert Millikan
He was able to find the unit charge of the electron in 1909 with his oil drop experiment.This allowed for the calculation of the mass of an electron and the positively charged atoms. -
Ernest Rutherford
He came up with the radioactive half-life. He also showed, through his gold foil experiment, that most of the mass an atom has is inside the nucleus and the space outside is mostly empty. His gold foil experiment showed that most of the particles went through the foil but 1 in 8000 particles was deflected leaving him to conclude that most of the mass is inside the nucleus and that all of the positive charge was inside the nucleus too. He was awarded Nobel Peace Prize for his work in this feild. -
Colorado
Colorado is admitted into the Union -
Neils Bohr
He had proposed the concept that electrons can only be in special orbitals. he proposed that elecrtons with more energy were farther from the nucleus and the electrons with less energy were closer to the nucleus. -
James Chadwick
He had discovered the existence to the neutron which almost directly led to the making of an atomic bomb -
Louis de Broglie
He believed that electrons can act like both particles and waves and he created the wave mechanic theory. -
Olympics
The first modern day olympics start in Athens -
Werner Heisenberg
He stated that electons do no travel in neat orbits. He also invented quantum mechanics. He also said that it was impossible to measure a quantum particle's position and momentum. -
Titanic
Titanic strikes an iceberg and sinks. -
Erwin Schrodinger
Created the Schrodinger Equation. He also introduced the term the eclectron cloud. -
World War II
World War II officially starts
