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Antoine Lavoisier
<a href='' >http://scienceworld.wolfram.com/biography/Lavoisier.html</a> His Traité Élémentaire de Chimie (Elementary Treatise of Chemistry, 1789) was the first modern chemical textbook, and presented a unified view of new theories of chemistry, contained a clear statement of the Law of Conservation of Mass, and denied the existence of phlogiston. it contained a list of elements, or substances that could not be broken down further, which included oxygen, nitrogen, hydrogen, phosphorus, mercury, zinc, and sulfur. -
Indivisible Solid Sphere Model
<a href='' >http://thehistoryoftheatomicmodel.weebly.com/the-solid-sphere-model.html</a>The Solid Sphere Model was the first atomic model and was developed by John Dalton in the early 19th century. He hypothesized that an atom is a solid sphere that could not be divided into smaller particles. He came up with his theory as a result of his research into gases. He realized that certain gases only combined in specific proportions. -
John Dalton
<a href='' >http://chemed.chem.purdue.edu/genchem/history/dalton.html</a> Experiments with gases that first became possible at the turn of the nineteenth century led John Dalton in 1803 to propose a modern theory of the atom based on the following assumptions:
1. Matter is made up of atoms that are indivisible and indestructible.
2. All atoms of an element are identical.
3. Atoms of different elements have different weights and different chemical properties.
4. Atoms of different elements combine in simple whole numbers to form compounds.
5. Atoms cannot be creat -
Joseph Louis Proust
<a href='' >http://chemed.chem.purdue.edu/genchem/history/proust.html</a> Between 1798 and 1808, Joseph Louis Proust analyzed different sources of several compounds. He found that they always contained the same ratio by weight of their elements. Table salt, for example, always contained 1.5 times as much chlorine as sodium. These results led Proust to propose the law of constant composition, which states that the ratio by mass of the elements in a chemical compound is always the same, regardless of the source of the compound. -
Michael Faraday
<a href='' >http://www.famousscientists.org/michael-faraday/</a> Historically, benzene is one of the most important substances in chemistry, both in a practical sense – i.e. making new materials; and in a theoretical sense – i.e. understanding chemical bonding. Michael Faraday discovered benzene in the oily residue left behind from producing gas for lighting in London. -
Henri Becuerel
<a href='' >http://www.biography.com/people/henri-becquerel-40055#scientific-work</a> In 1896, he made his greatest discovery: radioactivity. Following a discussion with Henri Poincaré on the recent discovery of X-rays, Becquerel devised an experiment that proved the existence of this naturally occurring force. Although his initial experiments were not successful he came upon evidence of natural radioactivity nearly by accident, when an unexpected reaction occurred in one of his laboratory drawers. Becquerel was awarded the Nobel Prize for Physics in 1903 w the Curies. -
JJ Thompson
<a href='' >http://www.aip.org/history/electron/jjelectr.htm</a>
JJ Thompson- or Sir Joseph John Thompson- was an english physicist. He came up with 3 hypothese about cathode rays. 1- that the rays were charged particles, that he called corpuscles. 2- the corpsucles are constituents of the atom. and 3- these corpsucles are the only constituents of the atom. these hypotheses led to the discovery of the protons, neutrons, and electrons, as well as their weights, within the atom. -
Marie Curie
<a href='' >http://www.biography.com/people/marie-curie-9263538#early-life</a> Marie's husband, Pierre put aside his own work to help Marie with her exploration of radioactivity. Working with the mineral pitchblende, the pair discovered a new radioactive element in 1898. They named the element polonium, after Marie's native country of Poland. They also detected the presence of another radioactive material in the pitchblende, and called that radium. -
Ernest Rutherford
<a href='' >http://chemed.chem.purdue.edu/genchem/history/rutherford.html</a> In 1899 Ernest Rutherford studied the absorption of radioactivity by thin sheets of metal foil and found two components: alpha (a) radiation, which is absorbed by a few thousandths of a centimeter of metal foil, and beta (b) radiation, which can pass through 100 times as much foil before it was absorbed. Shortly thereafter, a third form of radiation, named gamma (g) rays, was discovered that can penetrate as much as several centimeters of lead. -
Max Planck
<a href='' >http://www.pbs.org/wgbh/aso/databank/entries/bpplan.html</a> He was especially interested in the nature of radiation from hot materials. In 1901 he devised a theory that perfectly described the experimental evidence, but part of it was a radical new idea: energy did not flow in a steady continuum, but was delivered in discrete packets Planck later called quanta. -
Plum Pudding Model
<a href='' >http://www.universetoday.com/38326/plum-pudding-model/</a> The Plum Pudding Model is an atom model proposed by JJ Thomson, the physicist who discovered the electron. As a whole, the plum pudding representation only strived to explain why most atoms were neutral. -
Planetary Model
<a href='' >http://www.britannica.com/science/Rutherford-atomic-model</a> Proposed by Ernest Rutherford. The model described the atom as a tiny, dense, positively charged core called a nucleus, in which nearly all the mass is concentrated, around which the light, negative constituents, called electrons, circulate at some distance, much like planets revolving around the Sun. -
Albert Einstein
<a href='' >http://www.biography.com/people/albert-einstein-9285408</a> Albert Einstein was a German-born physicist who developed the general theory of relativity, among other feats. He is considered the most influential physicist of the 20th century. In November, 1915, Einstein completed the general theory of relativity, which he considered the culmination of his life research -
Robert Milikan
<a href='' >http://chemed.chem.purdue.edu/genchem/history/millikan.html</a>
Between 1908 and 1917, Robert Millikan measured the charge on an electron. The final result of his experiments stated that the mass of an electron is at least 1000 times smaller than the lightest atom, proving Thompson's hypotheses. -
Louis de Broglie
<a href='' >http://www.famousscientists.org/louis-de-broglie/</a> Louis de Broglie was an eminent French physicist. He gained worldwide acclaim for his groundbreaking work on quantum theory. In his 1924 thesis, he discovered the wave nature of electrons and suggested that all matter have wave properties. He won the 1929 Nobel Prize for Physics. -
Quantum Mechanical Model
<a href='' >http://www.dummies.com/how-to/content/atomic-structure-the-quantum-mechanical-model.html</a> The quantum mechanical model of the atom uses complex shapes of orbitals (sometimes called electron clouds), volumes of space in which there is likely to be an electron. So, this model is based on probability rather than certainty. -
Erwin Schrodinger
<a href='' >http://www.biography.com/people/erwin-schrdinger-9475545</a> Schrodinger was an Austrian physicist. He came upon the work of fellow physicist Louis de Broglie in 1925. In his 1924 thesis, De Broglie had proposed a theory of wave mechanics. This sparked Schrödinger's interest in explaining that an electron in an atom would move as a wave. The following year, he wrote a revolutionary paper that highlighted what would be known as the Schrödinger wave equation. -
Electron Cloud Model
<a href='' >http://www.regentsprep.org/regents/physics/phys05/catomodel/cloud.htm</a> The cloud model represents a sort of history of where the electron has probably been and where it is likely to be going. The red dot in the middle represents the nucleus while the red dot around the outside represents an instance of the electron. Imagine, as the electron moves it leaves a trace of where it was. This collection of traces quickly begins to resemble a cloud. -
Niels Bohr
<a href='' >http://www.biography.com/people/niels-bohr-21010897#wins-nobel-prize</a> He worked with Werner Heisenberg and other scientists on a new quantum mechanics principle connected to Bohr's concept of complementarity, which was initially presented at an Italian conference in 1927. The concept asserted that physical properties on an atomic level would be viewed differently depending on experimental parameters, hence explaining why light could be seen as both a particle and a wave, though never at the same time. -
James Chadwick
<a href='' >http://www.famousscientists.org/james-chadwick/</a> James Chadwick discovered the neutron in 1932 and was awarded the Nobel Prize for Physics in 1935. He led the British team in the Manhattan Project, in which the UK and Canada supported the USA’s World War 2 effort to build the world’s first nuclear bomb. -
Otto Hahn
<a href='' >http://www.famousscientists.org/otto-hahn/</a> Hahn made his most significant contribution to energy history in 1938. While working with Fritz Strassmann, a fellow chemist, he discovered that the element barium was produced when uranium atoms were bombarded with neutrons. -
Glenn T. Seaborg
<a href='' >http://www.chemheritage.org/discover/online-resources/chemistry-in-history/themes/atomic-and-nuclear-structure/seaborg.aspx</a> Glenn Theodore Seaborg (1912–1999) was involved in identifying nine transuranium elements (94 through 102) and served as chairman of the U.S. Atomic Energy Commission (AEC) from 1961 to 1971. In 1951 he shared the Nobel Prize in chemistry with the physicist Edwin M. McMillan.
