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Period: 700 BCE to
The Evolution of the Atom
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500 BCE
Concept of Atoms created
Ancient Greek philosophers Leucippus and Democritus are credited with proposing the idea that all matter is composed of tiny, indivisible particles known as atoms. -
500 BCE
Aristotle rejects the idea
Aristotle, a Greek philosopher, disagreed with the concept of atoms, believing that matter was continuous and not composed of discrete particles. -
Joseph Priestley's experiments with gases contribute to the understanding of chemical reactions.
Joseph Priestley's experiments in the late 18th century, including the discovery of oxygen, contributed to our understanding of chemical reactions. -
Antoine Lavoisier Conservation of Matter
He invented the law of Conservation of Energy, which is, energy cannot be generated or destroyed. He found it by doing an experiment that required heating mercury oxide. Its weight would drop and the oxygen that was released was equivalent to the amount the mercury oxide reduced. -
John Dalton's atomic theory proposes that matter is composed of indivisible atoms, each with its unique properties.
John Dalton's atomic theory in the early 19th century proposed that elements are composed of atoms, and chemical reactions involve the rearrangement of atoms. -
Max Planck
Max Planck largely researched thermodynamics throughout his life, and it's thermodynamics that made him so renowned. He was highly interested in radiation emanating from heated materials. He came up with a novel hypothesis which argued that energy did not flow gradually, but rather arrived in little packets called quanta. He felt this explained why a heated iron poker shone red and white. This notion transformed physics. -
Marie Curie
She and her husband found Polonium and Radium, determining that these were significantly more radioactive than Uranium. Also came up with the word radioactivity. She thought of this after analyzing so many elements sharing radioactivity. -
Dmitri Mendeleev develops the periodic table, organizing elements by atomic mass and predicting the existence of undiscovered elements.
around the year 1869 a russian scientist named Dmitri Mendeleev invented a new way of organizing the different type of atoms and elements that were known at the time, this was also the point that we started to see that there were gaps in the masses of our atoms and this let scientists see that there we atoms that we hadnt discovered yet that could be created. -
Albert Einstein mathematically proved the existence of atoms, and thus helped revolutionize all the sciences through the use of statistics and probability.
Albert Einstein, who is widely known for his contributions, to physics also made discoveries in the field of chemistry. He provided an explanation of the effect, which revealed the fundamental nature of light at a quantum level. This breakthrough had an impact, on our understanding of reactions and the behavior of atoms. As a result it revolutionized both chemistry and physics by revealing the exchanges of energy that occur on a scale. -
J.J. Thomson discovers the electron and proposes the "plum pudding" model of the atom.
In 1897, J.J. Thomson discovered the electron using cathode ray tube experiments, demonstrating that atoms contain subatomic particles. -
Ernest Rutherford conducts the gold foil experiment, leading to the discovery of the atomic nucleus and the development of the nuclear model of the atom.
In 1909, Ernest Rutherford conducted the gold foil experiment, revealing the presence of a small, dense nucleus within atoms, with electrons orbiting around it. -
Niels Bohr introduces the Bohr model, which describes electrons in specific energy levels or orbits around the nucleus.
Niels Bohr, a Danish physicist, introduced the Bohr model of the atom in 1913, which described electrons orbiting the nucleus in discrete energy levels. -
Louis de Broglie's wave-particle duality theory and Erwin Schrödinger's quantum mechanics revolutionize atomic theory.
in 1923 french physicist Louis de Broglie thought of the hypothesis that particles worked and moved like waves as well as particles by cutting 2 slots in a blocker/wall thing and shooting a electron beam gun at it and looking at the pattern that it would display on the surface it hit -
Werner Heisenberg
Heisenberg devised a new hypothesis based on what can be observed, such the radiation emitted by an atom. He felt that you couldn't put electrons in a definite position in time. In fact, he felt you couldn't even track an electron's orbit. Because of this conviction he argued that Bohr's model can't be correct. He argued that set values such as position and velocity could not be employed, he said that we should use abstract mathematical constructs called “matrices”. -
Modern understanding of atomic and subatomic particles
The development of quantum mechanics leads to the modern understanding of atomic and subatomic particles, including the electron cloud model and the Standard Model of particle physics.
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