The History Behind The Atom
Throughout the discovery of the atom, many scientists worked to formulate how the atom works. Which began in the early 1800’s with John Dalton, to our current model of the electron cloud developed by Schrodinger. During this long process of the discovery the atom, took many models and scientists. The entire group of scientists who assisted in the discovery of the atom used each other’s model to improve each other’s theories.
Firstly, John Dalton showed that, collectively, the three laws, the law of definite proportion, the law of conversation of masses, and the law of multiple proportion. These three laws demonstrate the existence of the atom. Also, Using these three laws he developed a theory called, Dalton’s Atomic Theory. This includes five basic principles; 1) all matter is made of indivisible and indestructible atoms, 2) atoms of a given element are identical in their physical and chemical properties, 3) atoms of different elements have different physical and chemical properties, 4) atoms of different elements combine in simple whole-number ratios to form chemical compounds, 5) atoms cannot be subdivided, created or destroyed when they are combined, separated, or rearranged in chemical reactions. However, after scientists look more carefully at his points they found some weaknesses. One weakness was that the atom was found to be indivisible, and they had smaller particles.
After Dalton came up with the five points, J.J. Thompson came along. He discovered that charged and magnets deflected the straight paths of cathode rays. In addition, he discovered negative and positive charged particles. He stated that the atom was made of smaller particles called, electrons and protons. In the discovery of the electron he used the Cathode-ray tube. As he researched he came up with a model of the atom, he stated that the atom was a ?plum pudding model.? This model featured negatively charged electrons embedded in a ball of positive charge.
After, J.J. Thompson came Ernst Rutherford, who was a student of Mr. Thompson. He created ?gold-foil experiment? which untimely-disproved J.J. Thompson’s theory. In this experiment he directed a beam of alpha particles at a very thin gold foil sheet. This was so the Rutherford could measure the angles of the particles coming off the gold foil. Sheet. Most of the alpha particles went through the sheet, however some of the particles hit the foil and bounced back. The reason of this was that the particles that bounced off the nucleus and the particles that went straight through traveled in the empty space. The major was that his experiment was that the atom would eventually lose its energy and collapse in the nucleus.
Around 1913, a Danish physicist named Niels Bohr came up with a new model to further our knowledge of the atom. In his model, he purposes that the electrons in the atom can reside only to certain energy levels. He related his model to a ladder, a person can stand on the rungs of the ladder, and however it is impossible for a person to stand between the rungs. The only way for the electron to jump to the next level is for it to have a Quantum leap. Which is the leap from one energy level to another, and the lowest energy level is called the ground state. Thus, comes to the conclusion that electrons are quantized. Helping Bohr’s model become superior, Plank declared that energy comes in packets or bundles of energy that is discontinued. This went all against classical science and he was not favored with the other scientist. Helping prove Bohr’s model he used the bright-line spectrum, which helped him prove his model. There was one flaw in his model, which was that it did not work with multiple elements.
After Bohr and Plank, another educated scientist came along who was DeBroglie, he purposed the Wave Particle Duality Theory. This theory stated that matter can act like waves, and waves can act like particles. To prove his theory he used the mathematical expression of mc=hc. Which meant that the m stood for the mass particles and the stood for the wavelength. Taking DeBroglie’s model to a further extent was Heisanburg; he treated electrons as particles. He came up with the uncertainly principal. In addition, he stated that the exact location of the electron couldn’t be determined. However, he could predict a region in space where the probability of finding the electron is high. This predicted region of high probability was named the electron cloud. The electron cloud was like a chaotic motion of electrons. However, Heisanburg did not treat the electron as a wave. On the other hand, Schrodinger considered the electron as a wave. Furthermore, he modified the wave equation, to form classical physics to fit the concept. In the equation, Schrodinger relates the probability region directly to the energy region. In the result of this action a plot of equations provides a three dimensional picture of the electron cloud. Schrodinger’s theory of the atom is our current model of the electron cloud.
Throughout, the existence of the atom many scientists came up with different models and ideas. Furthermore, each one of the scientists used one another to progress the model of the atom. With each one of the scientists contributing to the model, we were able to create a good model. By using the scientific method we gain the information of the atom, and we will continue to learn about it as more scientists come along.