brien.brown.atomichistory.fall.2010

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=//**__Atomic History Timeline __**//=

= = = = =__Ancient Times (450 AD and Prior) __=

=__Empedocles (ca. 490BC - ca. 430BC) __= Empedocles was a Greek philosopher who is credited with the original theory of the four classical elements. These four elements were Earth, Fire, Water, and Wind. He believed that powers called Love and Strife acted to combine and separate the elements and therefore were responsible for the workings of the universe, including the origin and advancement of life. Empedocles' theories are more based on religion and speculation than hard scientific fact. is why he is considered a an ancient philosopher and not an ancient chemist or physicist.It is not surprising however that Empedocles would reach such a conclusion on the workings of the universe. He worked in a time with little to no scientific technology and no prior understanding to the how the world work on the atomic level.

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= = = = =__Democritus (ca. 460BC - ca. 370BC) __= Democritus was a Greek philosopher originally born in Abdera, Greece. Many consider Democritus to be the father of modern physics and chemistry. He was the first to theorize that everything in the universe was formed by tiny, indivisible, indestructible particles that he named atoms (coming from the Greek word átomos, meaning uncuttable). Democritus also theorized that there were an infinite number of atoms, an infinite number of kinds of atoms, and that atoms were always in motion. Considering that Democritus had little to no technology to work with, it is amazing how accurate his theory of the atom is. For a man working more than 2000 years ago, Democritus' theory is incredibly close to that developed by scientist in this modern age. On a side note, Democritus was actually highly disliked by another famous Greek philosopher, Plato, who wished that all Democritus' books be burned.

[|http://www-unix.oit.umass.edu/~chappell/Images/Anc/demoju.jpg]

=__Aristotle (384 BC - 324 BC) __= Aristotle was an ancient Greek philosopher and student of Plato who was similar to many early chemists in the idea that he believed a theory much like that which stated everything was made of the four classical elements. However, Aristotle's atomic theory differed because he believed that a fifth element, aether, existed and made up all the heavenly bodies and spheres (i.e. stars and planets). It is understandable that Aristotle would make such presumptions about chemistry. He had no access to the modern technology available today, and was working off of hundreds of years of accepted theory based around the four classical elements.

[|http://www.astro.umontreal.ca/~paulchar/grps/site/images/aristotle.gif]

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= = = = = = = = = = **__1700 - 1800 __**

Joesph Black was a Scottish physician who is credited with the discoveries of latent and sensible heat, as well as carbon dioxide. Black's discovery of the two types of heat marked the beginning of the study of thermodynamics. By carrying out several consecutive experiments, Black was also able to create what he called "fixed air," but what we know as carbon dioxide. Black's observations led him to proclaim that carbon dioxide was produced by the process of respiration and micro bacterial fermentation. The invention of the analytical balance is also credited to Black as he designed it around 1750. Black worked in a stable time in history but with little available technology. The fact that he could learn what he did with the resources available to him is a credit to his intellect.
 * __Joseph Black (16 April 1728 - 6 December 1799) __**

[|http://www.chem.gla.ac.uk/~alanc/dept/black1.gif]

__**Antoine Lavoisier (26 August 1743 - 8 May 1794) **__ Antoine Lavoisier was a French who added major contribution to the world of chemistry with his research. He was the first to devise the law of conservation of mass, discovered and named oxygen and hydrogen, disproved the phlogiston theory, helped construct the metric system, helped reform chemical nomenclature, and wrote the first extensive list of elements. Lavoisier's experiments were some of the first quantitative experiments in history. They eventually showed him that although matter can change state and composition in a reaction, the amount of matter will remain the same, leading him to develop the theory of conservation of mass. Lavoisier also disproved the previously accepted phlogiston theory by combining his theory of conservation of mass with a number of experiments involving combustion. Lavoisier's contribution to chemistry are enormous and are even more incredible because of the time and place they were founded in. Lavoisier worked during the height of the French Revolutions, a perilous time for anyone. This would have limited his ability to access previous research, funds, and technology. The French Revolution would eventually cost Lavoisier his life, as in 1794 he was guillotined by French Revolutionists during the reign of terror.

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__**Henry Cavendish (10 October 1731 - 24 February 1810) **__ Henry Cavendish was a British scientist who is famed for his discovery of hydrogen, or what he called "inflammable air" at the time.Cavendish was able to created, isolate, and study hydrogen molecules by combining metals with strong acids. Through his experiments, Cavendish noticed that hydrogen reacted with oxygen during combustion to form water. Cavendish is also credited with accurately determining the composition of the Earth's atmosphere. Through his career Cavendish also worked with electrical forces and was one of the first to attempt the measure the density of the Earth. Cavendish's research overlapped much of the work being done by other scientist of the time. Much of Cavendish's work is similar to the work and the French scientist Antoine Lavoisier.

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= = =__<span style="font-family: 'Times New Roman',Times,serif; font-size: 25pt;">1800 - 1875 __=

=__<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">John Dalton (6 September 1766 - 27 July 1844) __= <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">John Dalton was an English chemist and physicist who is best know for his contributions to the modern atomic theory. Dalton theorized that ll things i <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">n the universe were made of tiny, indivisible, indestructible, spherical particles called atoms (much like the atomic theory of Democritus formed 2000 years earlier). Dalton also added five points to his theory. These points were: 1. All atoms of a given element are identical, 2. Atoms of one element are different from any other element and can be distinguished by their atomic weights, 3. Atoms can combine to form chemical compounds, 4. Atoms cannot be created, destroyed, or divided into smaller particles, and 5. Elements are made of tiny particles named atoms. Dalton also created the first periodic table of elements as seen on the left. Considering that Dalton had none of the modern technology we possess today, the fact he came as close as he did the an accurate atomic theory is just incredible as it was for Democritus. Dalton worked in a time with no computers, electricity, no highly accurate scientific tools, and no large base of understanding for the workings of the chemical world. The fact that he created the basis for our modern atomic theory with the resources he had available to him is incredible.

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<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Germain Hess was a Swiss born, Russian chemist who's famous work centered around Hess's Law. Hess's Law, one of the first laws ever devised about thermodynamics, states that the total enthalpy of a reaction that is carried out in steps is equal to the sum of the enthalpies of the individual steps. In other words, the sum of the energy required for each step is the total energy required to carry out a reaction. This law is an example of the law of conservation of energy. Hess's contribution serves the practical application that it is easier to calculate the overall enthalpy of a reaction when it divided into individual steps.
 * __<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Germain Hess (7 August 1802 - 30 November 1850) __**

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<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Lord Kelvin was an Irish scientist who made major contributions to the world of chemistry through his work involving thermodynamics. Kelvin is credited with creating the first two laws of the Laws of Thermodynamics. The first law describe the law of Conservation of Energy, while the second law states that the entropy of an isolated system never decreases (and also that perpetual motion machines are impossible). Lord Kelvin was also the first to develop the basis for absolute zero (a system with zero energy), and is credited with creating the Kelvin scale of measuring temperature. Kelvin worked in a stable time in history, and had access to good resources and technology for his time.
 * __<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Lord Kelvin (16 June 1824 - 17 December 1907) __**

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**__<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Dalton's Model of an Atom __** **__<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;"> (Tiny, spherical, solid, indivisible) __**

<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 12pt; text-align: center;">The first step in the modernly accept model of an atom was the model proposed by John Dalton and the scientists that preceded him. To Dalton, atoms were tiny, spherical, indivisible, solid particles that somehow attached to one another to form molecules. This model is the first step to the current model of atoms, but lacks much of the complexity found in an atom. Nothing is mentioned about any of the three types of subatomic particles, nor the placement of the electrons. Dalton's theory also proposed that atoms could not be separated in any way, and since the discovery of modern nuclear chemistry, this has been disproved.

= = = = =__<span style="font-family: 'Times New Roman',Times,serif; font-size: 25pt;">1875 - 1900 __=

=__<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Henri Becquerel (15 December 1852 - 25 August 1908) __= <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Henri Becquerel was French physicist who discovered radioactivity along with Marie and Pierre Curie. Becquerel accidentally discovered radioactivity when in 1896 he wrapped a fluorescent substance and photographic plate in a black cloth and placed them in a drawer in preparation for an experiment that required bright light. However, prior to the experiment, Becquerel discovered that the plates had already been exposed, causing an image of the substance to be shown. Becquerel won the Noble Prize for physics in 1903 along with Marie and Pierre Curie for their discovery of radioactivity. This discovery lead Becquerel to research further into the emission of radiation by certain substances. The time Becquerel worked in and his working conditions really played no role in his discovery. In reality his discovery was one of serendipity. [] []

=__<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Wilhelm C. Roentgen (27 March 1845 - 10 February 1923) __= <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Wilhelm C. Roentgen was a German physicist who in November of 1895 detected electromagnetic radiation in the <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">wavelength we know today as X-Rays. Two weeks after his initial discovery, Roentgen took the world's first X-Ray picture (of his wife's hand). He would win his first Nobel Prize for physics in 1901 for his discovery. Roentgen discovery was made with relatively simple technology (complex for his time), and he did work in a fairly stable time of history (prior to the onset of WWI). His discovery changed both the worlds of science and medicine. While his work helped us to understand more about electromagnetic radiation, it also saved the lives of countless people. Getting and X-Ray, a common occurrence now, would have been just been a fantasy before Roentgen's discovery.

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= = = = = = =__<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">JJ Thompson (18 December 1856 - 30 August 1940) __= <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">JJ Thompson was a British physicist who most famous work included the discovery of the electron and isotopes. Thompson would win the the 1906 Noble Prize in physics for his work with the electron. Thompson disproved the previously accepted theory that atoms were indivisible with his discovery that atoms contain tiny particles called electrons. Using the properties of cathode rays, Thompson was able to make this discovery. Thompson also concluded that electrons (which he actually originally named corpuscles) had to have to negative charge for the overall neutral charge of the an atom. He plum pudding model theorized that electron were negatively charged particles afloat in a sea of positively charge matter. He is also credited with the discovery of isotopes because of his research using canal rays and Neon gas. This research showed that his Neon sample was formed from Neon of two different masses. This is the first example of mass spectrometry in chemistry. Thompson's other work included the discovery of the natural radioactivity of potassium and that a hydrogen atom has only one electron, whereas previous theories allowed for different numbers. Like the other scientists of his time, Thomson worked in a generally stable environment (prior to the world wars) and had good technological resources for his time.

<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">[|http://www.physics.purdue.edu/~jones105/phys342l_Fall2008/jj_thompson.jpg] <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">[] <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">[|GBQCAP4AEVUCAQDGN3XCAXZ7RPHCA93YQROCA2YE6XJCAVVPFR0CA89OIEPCATFCHQBCAXNDKH1CA] <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">[|74IWILCADHVP2U.jpg]

**__<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Plum Pudding Atom Model __** [] <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 12pt; text-align: center;">The Plum Pudding Model of the atom was the work of the British scientist JJ Thompson, and was the second evolution of the atomic model towards our modern understanding. In 1904 (before the discovery of the nucleus), Thompson proposed that atoms were a solid core surrounded by negatively charged particles, known as electrons. Though the discovery of electron was a major step towards the modern understanding of atomic structure, the Plum Pudding Model still lacked much accuracy. Nothing is mentioned about the position of the electrons, nor the fact the neutral charge if an atom is unaccounted for due to the negative charge of electrons, nor the existence of protons or neutrons.

= = = = =__<span style="font-family: 'Times New Roman',Times,serif; font-size: 25pt;">1900 - 1915 __=

=__<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Marie Curie (7 November 1867 - 4 July 1934) __= <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Marie Curie was a Polish born French chemist and physicist who was a pioneer in the field of radioactivity. Notably, Marie Curie was the first person ever awarded two Nobel Prizes (chemistry and physics), and was also the first female professor at the University of Paris. Curie pioneered the study of radioactive elements with her research. She was the first to prove the existence of multiple elements experiencing radioactivity. By separating bitchblend and torbernite and analyzing them in her Curie meter (a device her husband and brother had invented to measure sensitive electrical charges), Curie was able to prove the existence of multiple radioactive elements. She was also able to prove that radiation was directly the result of the atom and not a reaction between molecules, arguably her most important contribution to the world of chemistry. What make Marie Curie's research even more astounding are the time she did it in and the working conditions she faced. The early 20th century was not kind to women in the world of science, and Curie faced sexism as she moved forward with her research. Curie also had no modern technology and poor working conditions. She invented her own machine to measure radioactivity. Finally, Marie Curie's working conditions provided her no protection from the harmful properties of radiation (although they were not know at the time), and this would cost her in the end as she would die in 1934 from aplastic anemia.

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= = = = =__<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Robert Millikan (22 March 1868 - 19 December 1953) __= <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Robert Millikan was an American physicist who is most famous for his work calculating the charge of an electron and for its photoelectric effect. In 1909, Millikan while serving as a professor at the University of Chicago used an oil drop experiment to measure the charge of a single electron.The oil drop experiment measured the force of tiny droplets of oil against the force of gravity in between two metal electrodes. By measuring the force of many droplets, Millikan was able to show that the cha <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">rge of a single as 1.592e-19 coulomb. Millikan would eventually win the Nobel Prize in 1923 for his discovery. Millikan also worked to disprove Einstein's theory that light could act as a particle which was published in 1905. Although all his research pointed to the fact that Einstein was in fact right, Millikan refused to believe that light could act in other nature other than a wave until when in 1958 he admitted in his book that Einstein was in fact right. Millikan's work came at a relative stable time in society. Though his career saw the fighting of two world wars, his research was not severely affected by either. He also had more powerful technology and equipment available to him than previous chemists had.

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=__<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Ernest Rutherford (30 August 1871 - 19 October 1937) __= <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Ernest Rutherford was a New Zealand born English chemist who many consider to be the father of modern nuclear chemistry. In 1908, <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;"> <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Rutherford won the Nobel Prize in Chemistry for his research into the radioactivity of elements. This was a year before his most famous work. In 1909, while trying to prove JJ Thompson's plum pudding model of an atom correct, Rutherford made several discoveries that changed the world of chemistry. During his famous Gold Foil experiment, Rutherford shot alpha particles at a thin sheet of foil foil, expecting the particles to pass directly through. In reality a small number of the particles deflected off in different deflections and even directly backwards (and were picked up by a screen surrounding the experiment). This result caused Rutherford to reassess the <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">current atomic thwory and he made a few changed as a result. First, Rutherford concluded that atoms were comprised of a tiny nucleus that contained a majority of the mass, surround by an electron cloud that took up the vast majority of the volume. Second that the electron orbited around the nucleus of the atoms, and were not just floating there like JJ Thompson had presumed. And finally, that atoms had a positively charged nucleus. Rutherford's discoveries were break throughs for the atomic theory. Rutherford worked in fairly stable time. World War one had yet to start and the world was, for he most part, at peace and stable. He also had better technology and more resources available to him than earlier chemists, but this does not take away from his discovery. Rutherford's work was another major step towards the atomic thwory we know today.

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=__<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Niels Bohr (7 October 1885 - 18 November 1962) __= <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Niels Bohr was a Danish physicist who received the Nobel Prize for physics in 1922 for his contributions in atomic structure and quantum mechanics. Bohr's most well know contributions to the modern atomic theory were his work on the Bohr and shell models of the atom. The Bohr model stressed the theory that electrons travel around the nucleus of an atom in specific circular orbits. The electrons orbit the nucleus like a planet orbits a star, but whereas gravity keeps a planet in orbit, an electron is held in orbit electrostatic forces. Bohr's shell model is basis for electron configuration. The shell model states that electrons are found in orbitals surrounding the nucleus of an atom, and are arranged from low to high energy levels. Niels Bohr also formulated the Correspondence Principle, which states that the behavior of systems described by the theory of quantum mechanics reproduces classical physics in the limit of large quantum numbers. Bohr also contributed during the years of the Second World War as he was part of the team of physicists working to build the atomic bomb for the Manhattan Project. He also ran an institution in Copenhagen, Denmark, and taught many of the greatest physicists of the 20th century.

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**__<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Planetary Model (Rutherford Model) __**

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<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 12pt; text-align: center;">The Planetary Model of an atom (also know as the Rutherford Model) was the result of the gold foil experiment made famous by the British chemist Ernest Rutherford. After observing particles pass through a thin sheet of gold foil, Rutherford hypothesized that atoms had a tiny, positively charged nucleus that contained the vast majority of an atom's mass, surrounded by an electron cloud that took up the vast majority of the volume of an atom. By try to prove JJ Thompson's Plum Pudding theory, Rutherford actually made the next step towards the modern atomic theory. Though Rutherford's model did discover the nucleus and correctly represent the scale of an atom, it did nothing to solve the placement of atoms and also did not mention the existence of protons or neutrons, only the overall positive nucleus.

**__<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Bohr-Rutherford Model __**

[] <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 12pt; text-align: center;">The Bohr Model of an atom states that an atom is a small positively charged nucleus surrounded by orbiting electrons that are electrostaticly attracted to the atom. The Bohr Model also beings to provide explanations for the placement of electrons, as the quantum numbers provided by Bohr state the energy level certain electron can be found on. Many sources refer to the Bohr Model as the Bohr-Rutherford Model because the Bohr model is simply a quantized model of the previous Rutherford Model. The Bohr Model begins to explain the positioning of electrons in the atom and is a major step towards our modern atomic structure theory. However, the Bohr Model still lacks a complete understanding of the nucleus and of the complete electron structure of an atom.

= = =__<span style="font-family: 'Times New Roman',Times,serif; font-size: 25pt;">1915-1950 __=

=__<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">James Chadwick (20 October 1891 - 24 July 1974) __= <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">James Chadwick was an English Noble Laureate in physics for his famed discovery of the neutron. In 1932, Chadwick discovered the neutron in the nucleus of an atom as it was previously unknown. He named it neutron for its lack of charge. A major breakthrough in the ability to create fission reactions, Chadwick's discovery was crucial to the creation of nuclear weapons. Unlike positively charged particles, neutrons do not have to overcome the electrical repelling forces of an atom and can therefore split even the heaviest atoms, creating a fission reaction. Chadwick's discovery allowed for the ability to create elements heavier than Uranium in the laboratory and caused others to research other similar reactions, such as slow fission reactions, which eventually lead to nuclear chemistry as we know it today. Chadwick was awarded the Noble Prize for physics in 1935 for his research and discoveries. Though his major work came before the onset of the second world war, Chadwick had good working conditions and a relatively stable working environment. He had good technology that was available at the time. Shortly after the onset of WWII, Chadwick joined the American Manhattan project to create the world's first atomic weapons, and was eventually knighted in England in 1945.

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=__<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Werner Heisenberg (5 December 1901 - 1 February 1976) __= <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Werner Heisenberg was a German theoretical physicist who is best know for his contributions to the field of quantum mechanics. Heisenberg's most well know contribution, the uncertainty principle of the quantum theory, states that certain pairs of physical properties (position, momentum, etc.) can not be measure to high precision. The more precise one is measure, the less precise the other will be able to be measured. In relation to chemistry, this principle states that it is impossible to measure both the position and velocity of an electron, or any other particle, with high accuracy. Heisenberg also worked on the matrix formula of quantum mechanics with several other physicists, which would win the the 1932 Noble Prize for physics. Like the other researchers of his time, most of Heisenberg's work came during peace time before and after the second world war. The fighting of a major war would have had significant impacts of Heisenberg's ability to carry out his research, and most likely would have cut his access to funding and new technology.

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=__<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Erwin Schrodinger (12 August 1887 - 4 January 1961) __= <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Erwin Schrodinger was an Austrian physicist who is considered as one of the fathers of quantum mechanics and is renowned for his contributions to chemistry and physics such as the Schrodinger equation, which won him the Noble Prize for physics in 1933.The Schrodinger equations describes how the quantum state of a physical system changes over time and is his most enduring practical contribution to the modern world. Schrodinger is also famed for his infamous cat hypothesis. The philosophical issues raised by Schrodinger's cat remain hotly debated to this day. In this hypothesis, Schrodinger stated that a cat, a poison, a source of radiation and a Geiger counter are all placed in a sealed box. If the Geiger counter detects radiations, a hammer breaks a flask containing the poison and kills the cat. What Schrodinger hypothesized is that after a while the cat is both dead and alive, but when we open the box, we can only see the cat as dead or alive. The experiment (which is completely a thought experiment) was meant to portray the bizarreness of quantum mechanics. Schrodinger also devoted part of his life to research of color and color perception, and published several papers on the topic. Like the other scientists of him time, Schrodinger worked in a relatively stable time, and had good access to the technology available to his generation. And as Schrodinger did not work on the Manhattan or similar projects, the onset of the second world war did not significantly interfere with his work.

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**__<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Electron Cloud Model (Orbital Model) __**



[] <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 12pt; text-align: center;">The Electron Cloud Model (also known as the orbital model) of an atom is the most modern understanding of the atomic structure of an atom. It is the result of the work of many chemist and physicists over several centuries. The Electron Cloud Model states that it is impossible to know both the position and momentum of an electron with certainty. Instead, the electron cloud model utilizes orbitals of consecutively higher energy levels that offer a prediction of where an electron may be.

=__<span style="font-family: 'Times New Roman',Times,serif; font-size: 25pt;">1950-modern day __=

__**<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Glenn T. Seaborg (19 April 1912 - 25 February 1999) **__

<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Seaborg was an American scientist credited with making discoveries in the chemistry of transuranium elements. Seaborg was born in Michigan and of Swedish decent. He kept a daily journal since 1927until he suffered a stroke in 1998. Seaborg had no interest in science until his junior year; his mother thought he should be a book keeper. Seaborg's interest in science was a result of his chemistry and physics teacher in high school. While at Ohio State University, one of Seaborg's professors invited him to meet Albert Einstein. That encounter had a profound effect on him as an aspiring student and scientist. Seaborg won the Nobel Prize in Chemistry in 1951 for his work with transuranium elements, the discovery and isolation of ten elements, and the development of the actinide concept. He is responsible for the current arrangement of the actinoid series in the periodic table of elements.

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 * __<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt; line-height: 15px;">Gerhard Herzberg (25 December, 1904 - 3 March 1999) __**

<span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Gerhard Herzberg was a German born physicist and physical chemist who was forced to flee as a refugee in 1935. Herzberg traveled around teaching for a few years before finally settling down in Canada. Herzberg's major contributions are to the field of atomic and molecular spectroscopy. He determined the structures of many diatomic and polyatomic molecules. He won the Nobel Prize for chemistry in 1971.

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