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US/World
The Civil War began when Fort Sumter was fired on in April of 1861. -
US/World
On November 19, 1863, President Lincoln gave one of the most important speeches. He reiterated the principles of human equality espoused by the Declaration of Independence. -
Chemistry_Law of Octaves
An arrangement of the elements that predated Mendeleev's periodic table; Newland's arrangement was a grouping of the elements in increasing atomic weights (starting with lithium) in horizontal rows of eight elements, with each new row directly beneath the previous one. -
US/World
On April 14, 1865 President Lincoln was assasinated by John Wilkes Booth at Ford's Theater in Washington, D.C. -
US/World
On February 24, 1868, for the first time in history, President Andrew Johnson was impeached. -
Chemistry-Mendeleev's Periodic Table
a systematic arrangement of the chemical elements. An earlier version was devised in 1869 by Dmitrii Ivanovich Mendeleev (Russian chemist, 1834-1907). By arranging the elements in order of their atomic weights, he was able to show relationships, such as valency, that occurred at regular intervals and was able to predict the properties of elements still undiscovered in the nineteenth century. -
Chemistry- Discovery of Electron
J.J. Thomson's discovery of the electron in 1897 showed us that the atom can be split into even smaller parts. His discovery was the first step towards a detailed model of the atom. -
US/World
On February 15, 1898, an explosion occurred on the USS Maine that caused the deaths of over 250 American sailors. This happened on the Havana Harbor -
Chemistry-Plum Pudding Model
The Plum Pudding Model is a model of atomic structure proposed by J.J. Thomson in the late 19th century. Thomson had discovered that atoms are composite objects, made of pieces with positive and negative charge, and that the negatively charged electrons within the atom were very small compared to the entire atom. He therefore proposed that atoms have structure similar to a plum pudding, with tiny, negatively charged electrons embedded in a positively charged substrate. -
US/World
The San Francisco earthquake was a major earthquake that struck San Francisco and the coast of Northern California at 5:12 a.m. on Wednesday, April 18, 1906. -
Chemistry-Rutherford's Gold Foil Experiment
The Gold foil experiment, or Geiger-Marsden experiment was an experiment done by Hans Geiger and Ernest Marsden in 1909, under the direction of Ernest Rutherford at the Physical Laboratories of the University of Manchester which led to the downfall of the plum pudding model of the atom. -
US/World
On April 14, 1912, the Titanic sunk by striking a huge ice berg that caused water to rapidly flow into the ship forcing it to sink. -
Chemistry- Bohr's Planetary Model of the Atom
In atomic physics, the Bohr model, introduced by Niels Bohr in 1913, depicts the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus—similar in structure to the solar system, but with electrostatic forces providing attraction, rather than gravity. -
Chemistry- Moseley/Atomic Numbers
Recently Moseley has supplied very valuable evidence that this rule [atomic numbers changing by one from element to element] also holds for a number of the lighter elements. By examination of the wave-length of the characteristic X rays emitted by twelve elements varying in atomic weight between calcium (40) and zinc (65.4), he has shown that the variation of wave-length can be simply explained by supposing that the charge on the nucleus increases from element to element by exactly one unit. -
US/World
World War 1 began after the Archduke of the Austro-Hungarian empire was assassinated in Sarajevo on June 28, 1914 by a group of Serbian nationalists. This was the first world war. -
Chemistry- Discovery of the Proton
The proton is a subatomic particle with the symbol p or p+ and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom. The number of protons in each atom is its atomic number. -
Chemistry-Schrodinger Equation
the fundamental equation of wave mechanics. -
US/World
The Great Depression which started on October 29, 1929 was a disaster that cost millions of Americans their jobs. Money was scarce and people were starving. -
Chemistry-Discovery of the Neutron
It is remarkable that the neutron was not discovered until 1932 when James Chadwick used scattering data to calculate the mass of this neutral particle. Since the time of Rutherford it had been known that the atomic mass number A of nuclei is a bit more than twice the atomic number Z for most atoms and that essentially all the mass of the atom is concentrated in the relatively tiny nucleus. -
US/World
The beginning of World War 2 was on September 1, 1939 when Adolf Hitler attacked Poland.
