Fall.2008.MMA.Cushman.Hutchinson.Timeline

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  Cushman and Hutchinson Present Their Atomic History Time Line Wiki Project 

**Democritus 460 BC- 370 BC Discovery Year- Ancient Times ** Democritus was born in 460 BC in Abderna Greece. Coming from a wealthy family he was given advantages that others were not. Traveling was common place in his family and he took advantage of it. He wrote many books while traveling to India, Asia, Ethiopia and more. Being craved for knowledge and being notable himself, he exchanged ideas and wisdom with many other philosophers and mathematicians. Unfortunately Plato was not pleased by many of his writings so had then discarded. Democritus did not originate the Atomic Theory but he helped summarize the principal doctrines. He became the first person in history to bring up the issue that there must be an empty area for the Atomic Theory to be true. He believed that everything was made of tiny particles called Atomos. The theory was that atoms are “infinite by number and imperceptible because of the minuteness of their size” and are always moving. In order for this to happen there had to be an area for the atom to move too which Democritus thought didn’t exist. This was a new way of thinking for chemistry at the time to think there was area with nothing in it.

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Sir Isaac Newton 1643-1727 **  Sir Isaac Newton was born in 1643 in England. He had a troubled house life as a child. His father  died 3 months before his birth. He disliked his step father and was angry at his mother for marrying him. It was recorded that at one point he wanted to kill them both by burning down their house. After his step father died his mother removed him from school and had him work as a farmer. Newton hated farming and demanded to be put back in school where he excelled past his years. They were being taught Aristotle but Newton preferred more advanced work such as Copernicus and Kepler. Newton is most popular for his Laws of motion. The first law states that a body at rest will stay at rest unless acted upon by an outside force. The second law Newton makes the connection of mass and acceleration to force. From this came the formula Force= (Mass) (Acceleration). The third law states that every action has an equal and opposite reaction. These are the 3 most important and basic laws in physics today. Without these laws there wouldn’t be a basis for Physics.


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Antoine-Laurent de Lavoisier ** **1743-1794 ** <span style="font-size: 14pt; font-family: 'Cambria','serif';"><span style="font-family: 'Cambria','serif';"><span style="font-size: 14pt; font-family: 'Cambria','serif';"><span style="font-family: 'Cambria','serif';">   <span style="font-family: 'Cambria','serif';">Antoine Lavoisier was born in 1743 in Paris, France. He was a wealthy boy and was taught during the French Enlightenment. He spent is time reading about chemistry, botany, astronomy and math. In 1763 he got a Bachelors degree in Law at the University of Paris. At the age of 28 he married a 13 year old who ended up being able to translate English papers for him. <span style="font-family: 'Cambria','serif';">Lavoisier is known as the father of modern chemistry. He stated the first Law of the Conservation of Mass which states that matter cannot be created nor destroyed. So even though matter can change its form, the atoms themselves will never be destroyed or created. This is a law upon which chemistry is built. He also created the first extensive lift of elements and introduced the metric system (he’s the one to blame).


 * <span style="font-size: 14pt; font-family: 'Cambria','serif';"><span style="font-size: 14pt; font-family: 'Cambria','serif';"><span style="font-size: 11pt; line-height: 115%; font-family: 'Cambria','serif';"> Charles du Fay  ** **<span style="font-size: 14pt; font-family: 'Cambria','serif';">1698-1739 ** <span style="font-size: 14pt; font-family: 'Cambria','serif';"><span style="font-size: 14pt; font-family: 'Cambria','serif';"><span style="font-size: 11pt; line-height: 115%; font-family: 'Cambria','serif';">[[image:Du_Fay.jpg align="left"]]   <span style="font-size: 11pt; line-height: 115%; font-family: 'Cambria','serif';">Charles du Fay is known for discovering that there are two different kinds of electricity. [[image:Du_Fay_2.jpg align="right"]]<span style="font-size: 11pt; line-height: 115%; font-family: 'Cambria','serif';">We know it now as positive and negative charges. From this he also realized that opposite charges attract and similar ones repel. This was a great break through for the time and now is common knowledge. He also disproved Dr. Steven Gray’s theory saying that electric properties depend on color. On top of this he also distinguished the difference between conductors and insulators.

Discovery Year- 1803 **John Dalton was born in Eaglesfield, England in 1766. He grew up a Quaker and helped his brother run a Quaker school. In 1973 he moved to Manchester. Dalton was color blind. Dalton suffered a minor stroke in 1837. He had a second stroke in 1838, which left him with a speech impediment. In May 1844 he had yet another stroke. In July 1844, in Manchester, Dalton fell from his bed and was found dead by his attendant.
 * John Dalton (6 September 1766 – 27 July 1844)

In 1803 Dalton came up with the atomic theory. The theory stated that all elements were comprised of small atoms. All atoms of a given element were identical. He figured that element could combine with each other to make substances. He was close in his guessing of the combination, but they were different from our modern understanding. He also proposed that atoms could not be divided, created, nor destroyed.

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Discovery Year- 1869** Dmitri Mendeleev was born in 1834 in Varhnie Aremzyani village, Russia. He was the youngest of 17 siblings. At the age of 13 he attended the Gymnasium in Tobolsk. In 1849 his family relocated to St. Petersburg, there he attended Main Pedagogical institute. After graduation he was diagnosed with tuberculosis which caused him to move to the Crimean Peninsula. He returned to St. Petersburg in 1857 after recovering from the disease. He married Feozva Nikitichina Leshcheva in 1862. By 1871 he had made St. Petersburg an internationally recognized center of chemistry research. He fell in love in 1876 with Anna Ivanova Popova and proposed to her, saying her refusal would result in his suicide. He married her in 1882 and divorced Leshcheva one month later. Mendeleev died in 1907 in St. Petersburg from influenza. The element mendelevium is named after him, as well as a crater on the moon.
 * Dmitri Ivanovich Mendeleev (8 February 1834 – 2 February 1907)

In 1869 Mendeleev formed the first periodic table. In this table he guessed several elements that would be discovered in the future. Mendeleev was criticized for this predictions because people couldn't believe that there were more elements. He was correct in his predictions and was very close to guessing the atomic weight of some of them. He cleared a path for scientists to discover new elements.

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Sir William Crookes (17 June 1832 – 4 April 1919) Discovery Year- 1875 **    <span style="font-family: 'Arial','sans-serif';">William Crookes was born in London, England in 1832. At the age of 15 he entered Royal College of Chemistry in Hanover Square, London. In 1856 he married Ellen Humphrey and had three sons and a daughter. In 1859 he founded the //Chemical News,// a science magazine. Crookes was knighted in 1897, and in 1910 received the order of merit. He died in London in 1919.

Crookes discovered the element Thallium in 1861. He also invented the Crookes tube in 1975, which investigated cathode rays. The Crookes tube was used by future scientists to make further discoveries of the atom, and eventually the discovery of X-Rays. The Crookes tube would make the atoms smash together causing them to lose electrons and have different charges. When the electrons would move back to their original energy level they emit a green light or a florescence. If an object was placed inside the tube the electrons would change direction, resulting in a silhouette of the object on the end of the tube. media type="youtube" key="Sikzu09q6cc" height="344" width="425" **Crookes Tube** <span style="font-size: 18pt; color: rgb(2, 60, 89); font-family: 'Arial','sans-serif';"> <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> <span style="font-size: 110%; font-family: 'Times New Roman',Times,serif;"> <span style="font-size: 110%; font-family: 'Times New Roman',Times,serif;">

Discovery Year- 1895** <span style="font-size: 110%; font-family: 'Times New Roman',Times,serif;"><span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> Wilhelm Conrad Rontgen was born on March 27, 1845, at Lennep in the Lower Rhine Province of Germany. When he was thr<span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> ee his family moved to Apeldoorn in The Netherlands. He was sent to the boarding school Institute of Martinus Herman van Doorn. In 1862 he attended a <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> technical school at Utrecht. He was wrongfully expelled, he was accused of drawing a picture of a teacher, but it was actually another student. After that he went to the University of Utrecht in 1865 to study physics. He became the Chair of Physics at the University of Munich in 1900. He remained there for the rest of his life. Rontgen died at Munich on February 10, 1923, from carcinoma of the intestine.
 * Wilhelm Conrad Rontgen (27 March 1845 – 10 February 1923)

Rontgen Invented the X-ray and won the Nobel prize for physics in 1901. In 1895, Rontgen was in a dark room trying to find substances that would become luminescent in the pitch black by passing a electric discharge through various vacuum tubes. By doing this he found that the rays would pass through aluminum and cardboard easily. He soon discovered that the rays would pass through flesh and bone. By projecting these rays he took a X-ray of his wife's hand. Where the rays passed through the flesh easier than the bones and a ring his wife was wearing. The outline of his wife's hand was made and the bones and ring were clearly visible. <span style="font-size: 110%; font-family: 'Times New Roman',Times,serif;">

<span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> <span style="font-size: 110%; font-family: 'Times New Roman',Times,serif;">**

Antoine Henri Becquerel (15 December 1852 – 25 August 1908) Discovery Year - 1896 ** Henri Becquerel was born in Paris, France in 1852. His family produced   4 generations of scientists. In 1982 he became the third of his family to take the physics chair at the Museum National d'Histoire Naturelle. He married Louise Désirée Lorieux in 1890, and had one son. His son went on to be a physicist. Becquerel died in 1908 in Le Croisic. The SI unit for measurement of radioactivity is named after him.

In 1896, while investigating the phosphorescence of uranium salts Becquerel accidentally discovered radioactivity. He placed the salts in a drawer on top of photographic plates, when he returned to carry out his original experiment he discovered that the plates were already fully exposed. The photographic plates had already been exposed. This led Becquerel to study nuclear radiation. He was awarded the Nobel prize for physics in 1903. <span style="font-size: 110%; font-family: 'Times New Roman',Times,serif;"> <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">

<span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> <span style="font-size: 110%; font-family: 'Times New Roman',Times,serif;"><span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">

<span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">**J.J. Thompson (1856** <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">**-1940) Discovery Year- 1897** <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">  <span style="font-size: 110%; font-family: 'Times New Roman',Times,serif;"><span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> Joseph John Thomson was born in Cheetham Hill, a suburb of Manchester on December 18, 1856. His father wanted him to be an engineer, but the Thompson family could not raise the necessary money for him to serve an apprenticeship. So Thompson attended Cambridge College in Manchester(1880), and was soon recommended to Trinity(1886). Thompson had a knack for science and made great advancements in it. He remained at Trinity the rest of his life, he went on to be a Lecturer in 1883 and Master in 1918. <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> J.J. Thompson was awarded the physics Nobel prize in 1906 for his discovery of the electron and other sub atomic particles. Thompson used cathode ray tubes (shown above) to discover the electron and other subatomic particles. He was knighted in 1908 and awarded the Order of Merit. In 1897, Thompson discovered the electron by filling a glass tube with air and running an electrical current through it. When the electrical current ran through the tube it brought the negative electrons towards it making a luminescent ray. This ray could be bent by the use of magnets, which showed it was made of smaller particles than just the atom. Thompson named these particles <span style="font-size: 110%; font-family: 'Times New Roman',Times,serif;">corpuscles, they were later identified as electrons. The video below shows how the electrons react to a magnet while in the cathode ray tube. <span style="display: block; font-size: 110%; font-family: 'Times New Roman',Times,serif; text-align: center;">media type="youtube" key="7YHwMWcxeX8" height="344" width="425" **Cathode Ray Tube** <span style="font-size: 110%; font-family: 'Times New Roman',Times,serif;"><span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> <span style="font-size: 14pt; font-family: 'Verdana','sans-serif';"> Marie Curie was born in 1867 in Warsaw, Russia. Growing up as the daughter of a s  econdary school teacher, she grew a great interest in learning. In 1894 she met Pierre Curie, a professor of physics. Together they became Head of the Physic department at Sorbonne. In 1906 her husband died and she took over the spot of Professor of general physics in the Faculty of Sciences, she was the first woman to hold that position. Working during World War I she used she research to help the cause. In 1898 she developed methods for the isolation of polonium. She also discovered how to separate radium from radioactive residues to study its characteristics. This radium was used to alleviate pain for soldiers during World War I. This was big because it highly developed the study of radioactive residues and also leads to advances in medicines. To those soldiers, this means of alleviation meant everything, and helped save lives.
 * Marie Curie 1867-1934  ****   Discovery Times- 1898   **<span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">   <span style="font-family: Arial,Helvetica,sans-serif;">    [[image:curiedffdsljfdslj32.jpg width="235" height="265" align="right" caption="curie 2"]]

<span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> **<span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">Ernest Rutherford <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">( 30 August 1871 – 19 October 1937)** **Discovery Year- 1907** <span style="font-size: 110%; font-family: 'Times New Roman',Times,serif;"><span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;"><span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">  <span style="font-size: 110%; font-family: 'Times New Roman',Times,serif;"><span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;"><span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">  <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;"><span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">  <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;"><span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">  <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;"><span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">  <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">Ernest Rutherford was the son of James Rutherford. Rutherford was born in Spring <span style="font-size: 110%; font-family: 'Times New Roman',Times,serif;"><span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;"><span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">   <span style="font-size: 110%; font-family: 'Times New Roman',Times,serif;"><span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;"><span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">  <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">Grove, New Zealand. After many accomplishments he traveled to England to study <span style="font-size: 110%; font-family: 'Times New Roman',Times,serif;"><span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;"><span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">   <span style="font-size: 110%; font-family: 'Times New Roman',Times,serif;"><span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">at the University of Cambridge. Soon after that he was appointed chair of physics at McGill University in Canada. He married Mary Georgina Newton and they had one daughter. <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';"> Ernest Rutherford was known as the father of nuclear physics. He was knighted in 1914. He was awarded the chemistry Nobel prize in 1908. With his gold film experiment he discovered the orbital theory of the atom. In 1907 <span style="display: block; font-size: 110%; font-family: 'Times New Roman',Times,serif; text-align: center;"><span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;"><span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">  <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">Rutherford shot alpha particles through a thin piece of gold foil. Rutherford was shocked and intrigued when the particles deflected in different directions. He thought the atoms would pass through the gold foil without any major disruptions. Due to the results, Rutherford was able to conclude that there was a tiny internal structure with a heavy charge that was able to deflect the atoms in different directions. This destroyed the theory of a plum pudding model and gave chemists something new to discover.

media type="youtube" key="5pZj0u_XMbc" height="344" width="425" **Rutherford's Gold foil Experiment**

Discovery Year- 1909 ** <span style="font-size: 110%; font-family: 'Times New Roman',Times,serif;">Millikan was an American physicist. He was born in 1868 and raised in Illinois. He attended Oberlin College and Columbia University, receiving a Bachelor's degree at both. He received a Ph.D from Columbia University for physics and was the first to do that in that department. In 1921 he became the president of California Institute of Technology. He went on to marry Greta Ervin Blanchard and have three kids.
 * Robert Andrews Millikan (March 22, 1868 – December 19, 1953)

In 1909, Millikan discovered the charge of an electron (1.592 × 10−19 coulomb) which is really close to the actual charge of an electron (1.602 x 10−19 coulomb). He discovered this with Harvey Fletcher, but took solo credit for it as long as he kept the secret of his partners dissertation. His experiment with the oil droplets helped further the belief of sub-atomic particles. He went on to win the Nobel prize for physics in 1923, in part for this discovery. media type="youtube" key="XMfYHag7Liw" height="344" width="425" **Millikan's Oil Drop Experiment**



Niels Henrik David Bohr 1885- 1962 **** Discovery Time-1911 ** Niels Bohr was born in Copenhagen as the son of Christian Bohr, the Professor of Physiology at Copenhagen University. His father has a lot to do with awakening his interests in physics as a young boy. While still a student, he would use his father’s laboratory to investigate the theoretical abilities of surface tension by means of oscillating fluid jets. This work got him a gold medal and he was published in the Royal Society in 1908. Niels Bohr, while studying the structure of an atom in 1911, created a new and advanced version of the Plum Pudding model. This version has tracks which negatively charged electrons rotating around a positively charged nucleus. It was quite a significant discovery because it explained the Rydberg Formula and gave justification to the empirical results in the fundamental constants that are used in physics. With only slight modifications, this is still the model of an atom that everyone believes to be correct.

<span style="font-size: 8pt; line-height: 115%; font-family: 'Verdana','sans-serif';"> **

Werner Heisenberg ** Werner Heisenberg was born in 1901 in Wurzburg, Germany. His father was a Professor of the Middle and Modern Greek Languages in the University of Munich. He went to the Maximillian School at Munich until 1920. Heisenberg took his PHD at the University of Munich in 1923. From 1924-1925 he worked with Niels Bohr at the University of Copenhagen. During World War II he was taken prisoner by American troops but was released by 1946, this restricting his studies. He is known for his Quantum Theory of Mechanics in 1925. This basically said that electrons have no specific place or orbit in an atom but a random movement. It also goes in depth to explain the scale of an atoms shape and build with position and velocities. It is given credit for aiding the discovery of allotropic forms of hydrogen. This is the most modern form of atom that we know and learn today.
 * 1901-1976 **
 * Discovery Time- 1925 **

**   Erwin Rudolf Josef Alexander Schrodinger ( 12 August 1887 – 4 January 1961) Discovery Year- 1926 **                                                                                       Erwin Schrodinger was an Austrian physicist. He was born in 1887 in Vienna, Austria. In 1920 Schrodinger married Annemarie Bertel. In 1921 he moved his                                    studies to the University of Zurich. During the Nazi reign, Schrodinger fled Germany back to Austria. When Germany invaded Austria, he issued a statement recanting his opposition of the Nazi beliefs. He later took that statement back and apologized to Einstein personally. He lost his job for political unreliability. The war made it tough for him to fallow through with his studies. He fled Austria to Italy, after being instructed not to. In 1940 he helped establish an Institute for Advanced Studies in Dublin, Ireland. Schrodinger died in 1961 in Vienna, Austria of tuberculosis. In January 19 1926, Schrodinger published the paper "Annalen der Physik", a paper on wave mechanics. The paper is now known as the Schrodinger equation. The paper showed the correct energy values for the hydrogen atom. The paper is known as one of the most important achievements of the 20th century. He released 3 more papers, one solving the quantum harmonic oscillator and the rigid rotor, another gave treatment to the Stark effect, and the last showed how to treat problems in which the system changes with time. The papers made Schrodinger well known, and were the center of his achievements. He received the Nobel prize in 1933 for his extensive studies of Quantum Mechanics. **<span style="font-size: 8pt; line-height: 115%; font-family: 'Verdana','sans-serif';">James Chadwick ** **1891-1974** **Discovery Time-1932** James Chadwick was born in Cheshire, England in 1891. In 1911 he graduated from the Honours School of Physics and spent the next couple years studying under Professor Rutherford. During World War I he was interned in the Zivilgenfangenenlager, Ruhleben. After the War he returned home to work under Rutherford again. In 1932, he discovered the existence of neutrons. These are particles in the nucleus that do not have a charge. Since this new set of particles do not have an electrical charge to repel others, the idea of splitting an atom became a believable idea. With this discovery Chadwick started the man idea for the atomic bomb after showing that fission of Uranium 235. Two atomic bombs were given the credit to ending the conflict with Japan during World War II, saving millions of American soldiers in avoiding a siege of the islands.

= Models =

Small, Spherical, Solid, Indivisible Model

<span style="font-family: 'Cambria','serif';">This is the first model of an atom. Democritus believed that everything was made of small particles that he called Atomos. Everything around him was made of an infinite amount of atoms. It’s just a sphere that cannot be divided and is too small to be seen. This sphere is solid and is the smallest form of division of any object. It was later enhanced by the Plum Pudding Model.

<span style="font-size: 16pt; font-family: 'Cambria','serif';">The Electron Cloud Model

<span style="font-family: 'Cambria','serif';"> This is the Atomic Cloud Model. Contrary to other models it has an electron cloud instead of tracts on which the electrons flow. Instead it takes into account that the paths of electrons are unpredictable and random. The electrons are freely moving within the electron cloud of every atom. This was discovered by Werner Heisenberg around 1925 and is a part of the Quantum Theory of Mechanics.

<span style="font-size: 16pt; line-height: 115%; font-family: 'Cambria','serif';"> Plum Pudding Model <span style="font-family: 'Cambria','serif';">This is the Plum Pudding Model and it was created by JJ Thomson in 1904. It suggests that there are small particles called electrons that are negatively charged floating around in a positively charged soup like substance. This was advancement from the belief that an atom is just a small indivisible ball. The small particles    were originally called corpuscles by Thomson but because of its electrical charge GJ Stoney suggested the name electron. After the discovery of the nucleus in 1909, this was no longer used.


 * Bohr/ Rutherford Planetary Model** [[image:h-levels.gif align="left" caption="Graph of Energy Levels"]][[image:bohr2.gif align="right" caption="Planetary Model"]]The Bohr/ Rutherford model or more commonly known as the Planetary model was created in 1915. It shows a nucleus with electrons circling the nucleus. The nucleus is comprised of subatomic particles. Unlike past model the model shows electrons orbiting the nucleus, where others showed the subatomic particles scattered throughout the nucleus. The planetary model shows different energy levels for the electrons. These energy levels have higher energy as they get farther away from the nucleus.

Works cited- John Dalton- http://www.chemheritage.org/classroom/chemach/periodic/dalton.html Dmitri Mendeleev- http://www.answers.com/topic/dmitri-mendeleev William Crookes- http://www.answers.com/topic/william-crookes JJ Thompson- http://www.chemheritage.org/classroom/chemach/atomic/thomson.html Ernest Rutherford- http://nobelprize.org/nobel_prizes/chemistry/laureates/1908/rutherford-bio.html Antoine Becquerel- http://nobelprize.org/nobel_prizes/physics/laureates/1903/becquerel-bio.html Wilhelm Rontgen- http://nobelprize.org/nobel_prizes/physics/laureates/1901/rontgen-bio.html Robert Millikan- http://nobelprize.org/nobel_prizes/physics/laureates/1923/millikan-bio.html Erwin Schrodinger- http://nobelprize.org/nobel_prizes/physics/laureates/1933/schrodinger-bio.html <span style="font-size: 8pt; font-family: 'Verdana','sans-serif';">