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The Importance of Atomic Theory
atomic theory creation
atomic theory creation
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The idea of atom existed as early as the Greek and Indian civilizations, but more as a philosophical thought rather than a well-defined theory based on empirical evidence. Atom was assumed as something that is indestructible and the smallest component that makes up matter. It took almost 2000 years for the development of modern day atomic theory with proof for the existence of atoms and further subatomic particles. The archaeological classification of human history as stone age, bronze age and iron age depicts the evolution of macroscopic chemistry first. Much later through the fundamental studies in electromagnetism and blackbody radiation, the discovery and theoretical formulation
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Hohenberg and Kohn (1964), Kohn and Sham (1965) published two seminal papers laying a strong foundation for Modern Density Functional Theory (DFT). They found that the wave function is over specified (similar to Dirac 's observation) and a two electron probability density is good enough to get the molecular energy. DFT formalism has a lot of inherent assumptions, such as Local Density Approximation and the choice of functional has to be tackled carefully [5]. The main advantage of DFT is its ability to handle large systems and the low computational cost associated. Also DFT can be employed to get the interaction potentials in Molecular Dynamics runs thus incorporating a more accurate description of underlying electronic potentials. DFT helps in the calculation of a wide range of molecular properties of real physical significance. DFT spurred the growth of solid state physics. Peter Puschnig [6] gave an extensive list of DFT applications which are reproduced here: Structural properties (lattice parameters, elastic constants, equilibrium geometry, etc.), electronic structure (band structure, density of states), lattice dynamics (vibrational frequencies, phonon density of states, vibrational entropy), electron density (charge rearrangements, electric field gradients), spectroscopy (photoemission, optical absorption, Raman scattering, Compton scattering,
Attempts to organize the elements began in the late 1800’s. At this time, about sixty elements were known. Much advancement would have been impossible if the basic model of the atom was discovered. Great progress came from Dmitri Medeleev – a Russian chemist. His first draft of a periodic table was only the product of him attempting to summarize his knowledge of the elements. Although not all of Medeleev’s ideas were one-hundred percent accurate, they created a solid base to build upon. Marie and Pierre Curie; a married couple from Paris were successors of Medeleev. Their interests were radioactivity and discovered radium. The true pioneers of the periodic table were Ernest Rutherford and James Chadwick. Rutherford formed the hypothesis that, “An atom must have a concentrated positive center charge that contains most of the atom’s mass.” Following Rutherford, Chadwick exposed a segment of the nucleus that was had no charge: the neutron. With the basic knowledge of the structure of an atom, the tedious work of putting the rest of the puzzle together continued.
The cathode ray tube was invented in 1875 by the name of Sir Williams Crooke. Yet he wasn’t the one to make the big discovery. In 1897, a man by the name of J.J. Thompson conducted a series of experiments to prove the existence of subatomic particles. He wasn’t 100% correct with all of his claims he made but broke the theory John Dalton stated that the smallest form matter could be broken down to was an atom. Having shown the world that there was smaller than an atom, it later caused others to question and dive even deeper.
...the first version of the atomic theory, which then later allowed John Dalton to expand on the atomic theory to create a method of discerning atomic weight, was crucial in the development in the table. It was through finding the atomic weight of elements as well as classifying their properties that allowed Mendeleev to create his periodic table and discern possible new elements.
Dalton’s atomic theory, which stated “the atoms were tiny, indivisible, indestructible particles” (Bender), differed drastically from that of the Greeks’ in that it “wasn’t just a philosophical statement that there are atoms because there must be atoms” (Bender). Although Aristotle believed that there are four terrestrial elements, earth, water, air, and fire, Democratus believed that “a piece of a substance can be divided into smaller pieces of that substance until we get down to a fundamental level at which you can’t divide the substance up and still have pieces of that substance” (“Atoms”). Aristotle’s theory was popular, but incorrect; Democratus’s was closer to our current theory, yet he remained relatively unpopular and obscure. This demonstrates of the key way in which a personal point of view can, in fact, retard the pursuit of knowledge. The scientist with the better oratory abilities has his theories more widely accepted. Dalton’s own theory, which extrapolated upon four basic
Although atomism certainly was not a new philosophy by the time Lucretius wrote, or even by the time of Rome’s ascension to power, the original propositions regarding the nature of matter were not enough to construct a philosophy similar to that presented by Lucretius. Over time, atomism had evolved from a binary view that the world consisted solely of atoms and void, ...
In 1911, Ernest Rutherford found a very spectacular in such a small thing. Rutherford found that an atom has a microscopic charged nucleus. Empty space surrounds the nucleus. The nucleus is also surrounded by electrons. By this discovery Rutherford made the model of the atom.
Many scientists helped with this. In 465 B.C. Democritus named the atom “can’t be divided” (OI). He proposed that matter was made of atoms (Doc. 1). Later, Lavoisier introduced the Law of Conservation of Matter. It stated that matter couldn’t be created or destroyed. After that, John Dalton published the Atomic Theory of Matter in 1803 (Doc. 2). It said that matter is made of atoms that are too small to be seen by the naked eye, and that each type of matter is made of only one kind of atom (OI). J. J. Thomson observed electrons using cathode rays. A few years later, Ernest Rutherford bombarded an extremely thin piece of gold foil with positively charged alpha particles. Most of the protons passed through the foil, but some bounced off. Rutherford concluded that the atom must be composed of mostly empty space. He also realized that the alpha particles must have bounced off something else that had positive charge. The positively charged objects were protons. Neutrons were discovered by James Chadwick. To conclude, the theories of the atom have been modified a lot since the
The main theory of the day, with regard to physical science, was Atomism. Atomists believed that bodies are made from minute particles. Further, they believed that the particles and the bodies made from them, possess primary and not secondary properties. The most important exception from this viewpoint was that of Descartes. Although he rejected atomism, he did agree that bodies only really possess primary qualities. Basically what this means is that bodies in themselves possess shape, size, motion and impenetrability but not colour, sound, taste, hardness or smell. This latter g...
They new the structure and particle makeup of atoms, as well as how they behaved. During the 1930Õs it became apparent that there was a immense amount of energy that would be released atoms of Gioielli 2certain elements were split, or taken apart. Scientists began to realize that if harnessed, this energy could be something of a magnitude not before seen to human eyes. They also saw that this energy could possibly be harnessed into a weapon of amazing power. And with the adven...
In 1803 this theory was finalised and stated that (1) all matter is made up of the smallest possible particles termed atoms, (2) atoms of a given element have unique characteristics and weight, and (3) three types of atoms exist: simple (elements), compound (simple molecules), and complex (complex molecules).
For centuries, physicists and philosophers alike have wondered what makes up our universe. Aristotle thought that all matter came in one of four forms: Earth, Air, Fire, and Water. Since then we have come a long way, with the discovery of the atoms and the subatomic particles they are made of. We can even guess at what makes up protons and neutrons. We have since then discovered and predicted the existence of particles other than the atom, such as the photon, neutrino, axion, and many others.
The idea of the atom started all the way back from the ancient Greece. What is sad about this is that one philosopher’s idea it was rejected by the rest of the philosophers of the time. Philosophers like Aristotle. The ancient Greeks did not have all the modern technology we have now and were not equipped to test their atomic theory. The theory they had hypothesized was if you keep dividing something, the smallest living thing had to be an atom.
The Atomic Theory began in roughly 400BC with Democritus in Ancient Greece and is universally believed to be correct today. Democritus who was born in 460 BC and died 370 BC and is known as the father of modern science. Democritus proclaimed that everything is made up of atoms. He continued his theory to say that atoms will always be in motion, between atoms there is empty space, atoms are unbreakable, there are an infinite number of atoms all different sizes and shapes. He also said that iron atoms are solid and strong and have hooks to lock them together, water atoms are smooth and slippery, salt atoms have sharp jagged edges because of its taste and air atoms are light and spiralling.
Things are very different from each other, and can be broken down into small groups inside itself, which was then noticed early by people, and Greek thinkers, about 400BC. Which just happened to use words like "element', and `atom' to describe the many different parts and even the smallest parts of matter. These ideas were around for over 2000 years while ideas such as `Elements' of Earth, Fire, Air, and Water to explain `world stuff' came and went. Much later, Boyle, an experimenter like Galileo and Bacon, was influenced much by Democritus, Gassendi, and Descartes, which lent much important weight to the atomic theory of matter in the 1600s. Although it was Lavoisier who had divided the very few elements known in the 1700's into four different classes, and then John Dalton made atoms even more believable, telling everyone that the mass of an atom was it's most important property. Then in the early 1800's Dobereiner noted that the similar elements often had relative atomic masses, and DeChancourtois made a cylindrical table of elements to display the periodic reoccurrence of properties. Cannizaro then determined atomic weights for the 60 or so elements known in the 1860s, and then a table was arranged by Newlands, with the many elements given a serial number in order of their atomic weights, of course beginning with Hydrogen. That made it clear that "the eighth element, starting from a given one, is a kind of a repeat of the first", which Newlands called the Law of Octaves.
Scientists from earlier times helped influence the discoveries that lead to the development of atomic energy. In the late 1800’s, Dalton created the Atomic Theory which explains atoms, elements and compounds (Henderson 1). This was important to the study of and understanding of atoms to future scientists. The Atomic Theory was a list of scientific laws regarding atoms and their potential abilities. Roentagen, used Dalton’s findings and discovered x-rays which could pass through solid objects (Henderson 1). Although he did not discover radiation from the x-rays, he did help lay the foundations for electromagnetic waves. Shortly after Roentagen’s findings, J.J. Thompson discovered the electron which was responsible for defining the atom’s characteristics (Henderson 2). The electron helped scientists uncover why an atom responds to reactions the way it does and how it received its “personality”. Dalton’s, Roentagen’s and Thompson’s findings helped guide other scientists to discovering the uses of atomic energy and reactions. Such applications were discovered in the early 1900’s by using Einstein’s equation, which stated that if a chain reaction occurred, cheap, reliable energy could b...