Group2

RGroup 2: Andrew, Sophia, Tyler, Taylor John Dalton John Dalton was born into a Quaker family in the early 1800s, at the age of 12 he became a teacher and pursued it as a career at the age of 15. Dalton first took an interest in being a meteorologist after rediscovering atmospheric circulation, Dalton took up chemistry. From an earlier chemist named Democritus Dalton created the atomic theory.

The theory states:
 * All matter is made of indivisible partials that are too small to see with the naked eye called Atoms.
 * All atoms in one element are identical to each other in size and weight.
 * Atoms of a different element have different atoms.
 * Atoms of two different elements can be combined to create a new substance.

From Democritus Dalton reconsidered the idea that each different kind of element is made of a different kind of atoms. Work and experiments led him to think that all atoms were like very small spheres but that they could have different properties such as weight and size, most of Daltons theory was from deductive reasoning. As Dalton was a meteorologist he recognized that water evaporates and studied why it happened, while trying to explain that he determined that partials making up gases must be different in size and weight. John Dalton has inspired and has helped J.J Thomson with his atomic theory.

Picture of John Dalton’s atomic theory model. John Dalton also used a circle with a C to represent Carbon. In this model you can clearly see the way Dalton visions the atoms, however you can not see what sphere represents which atom.  Picture from: [|__http://www.xtimeline.com/evt/view.aspx?id=397725__]

<span class="TextRun SCX200650457" style="font-family: Calibri,Sans-Serif; font-size: 14.66px;">Other references: Pearson Saskatchewan science 9 <span class="TextRun SCX200650457" style="font-family: Calibri,Sans-Serif; font-size: 14.66px;"> : Jaylene Timeline 1 | An Atomic Theory Takes Shape | Event view. (n.d.). xtimeline - Explore and Create Free Timelines. Retrieved September 16, 2011, from http://www.xtimeline.com/evt/view.aspx?id=397725

<span class="TextRun SCX200650457" style="font-family: Calibri,Sans-Serif; font-size: 14.66px;"> : John Dalton atomic theory. (n.d.). university today. Retrieved September 16, 2011, from [|www.universetoday.com/38193/john-daltons-atomic-theory/]
 * __<span style="font-family: Arial,Helvetica,Geneva,Swiss,SunSans-Regular;">Ernest Rutherford b __****__<span style="font-family: Arial,Helvetica,Geneva,Swiss,SunSans-Regular;">y:Tyler __**

(picture from [] ) Ernest Rutherford published his atomic theory describing the atom as having a central nucleus that has a positive charge surrounded by orbiting electrons that have a negative charge similar to planets orbiting the sun. This theory states that most of the mass of the atom is in the small nucleus and the rest of the atom is mostly empty space. Rutherford proved this following the events of his gold foil experiment (seen above). This experiment used the firing of radioactive particles through extremely thin metal foils such as gold and detecting them using screens coated with zinc sulphide. Rutherford discovered that the mass majority of the particles passed straight through the foil about 1 in 8000 where deflectied guiding him to the theory that atoms are mostly empty space.I think this model is effective because he proved that most of the mass of the atom is in the centre. However Rutherford did not have any proof that the elections orbit the nucleus.

(Picture from: [] ) Rutherford atomic model representing carbon.

bibliography:
 * Ernest Rutherford | Chemical Heritage Foundation. (n.d.). Homepage of the Chemical Heritage Foundation | Chemical Heritage Foundation. Retrieved September 13, 2011, from []
 * Rutherford - Atomic Theory. (n.d.). Royal Society of Chemistry, the largest organisation in Europe for advancing the chemical sciences. Retrieved September 14, 2011, from
 * Atom Diagram. (n.d.). //Universe Today — Space and astronomy news//. Retrieved September 16, 2011, from []

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<span style="color: #082591; font-family: Arial,Helvetica,sans-serif; font-size: 26.6667px;"> By: Taylor
<span style="font-family: Arial,Helvetica,sans-serif; font-size: 110%;">Joseph John Thomson was born in 1856 in Cheetham Hill, Manchester England His mother, Emma Swindles, came from a local textile family. His father, Joseph James Thomson, ran an antiquarian bookshop founded by a great-grandfather from Scotland (hence the Scottish spelling of his surname). He had a brother two years younger than him, Frederick Vernon Thomson. Thomson was awarded the 1906 Nobel Prize in Physics for the discovery of the electron and for his work on the conduction of electricity in gases.

<span style="font-family: Arial,Helvetica,sans-serif; font-size: 110%;">Thomson believed that the corpuscles emerged from the atoms of the trace gas inside his cathode ray tubes, also in 1897 Thomson was the first to suggest that the fundamental unit over 1000 times smaller than an atom.

His early education took place in small private schools where he demonstrated great talent and interest in science. In 1870 he was admitted to Owens collage Being only 14 years old at the time, His parents planned to putt him as an apprentice engineer to Sharp-Stewart & co, a locomotive manufacturer, but these plans were cut short when his father died in 1873.He moved on to Trinity collage, Cambridge in 1876. In 1880, he obtained his BA in mathematics ( Second Wrangler and 2nd Smiths prize) and MA (with Adams prize) in 1883. In 1884 he became Cavendish professor of physics.

J.J discovered this through his explorations on the properties of cathode rays. Thomson made his suggestion on 30 April 1897 following his discovery that Lenard Rays could travel much further through air than expected for an atomic-sized particle.He estimated the mass of cathode rays by measuring the heat generated when the rays hit a thermal junction and comparing this with the magnetic deflection of the rays. His experiments suggested not only that cathode rays were over 1000 times lighter than the hydrogen atom, but that their mass was the same. whatever type of atom they came from, he concluded that the rays were composed of very light, negatively charged particles which were a universal building block of atoms. J.J had called them "corpuscles"

To explain the overall neutral charge of the atom, he proposed that the corpuscles were distributed in a uniform sea of positive charge; this was the "plum pudding" model—the electrons were embedded in the positive charge like plums in a plum pudding (although in Thomson's model they were not stationary, but orbiting rapidly).

Above Is J.J. Thomson's version of the atomic model
__ **Weaknesses** __
 * Thomson couldn't find the electrons that were in specific energy levels around the nucleolus

__ **Strengths** __
 * it was probably the first atomic model that included the electrons
 * the sphere was actually positively charged.

__** References **__ > http://www.chemheritage.org/discover/chemistry-in-history/themes/atomic-and-nuclear-structure/thomson.aspx > http://www.scienceclarified.com/As-Bi/Atomic-Theory.html > http://www.clickandlearn.org/gr9_sci/atoms/modelsoftheatom.html
 * J. J. Thomson - Wikipedia, the free encyclopedia - http://en.wikipedia.org/wiki/J._J._Thomson retrieved @ 4:35 October 16th.
 * Pearson Saskatchewan Science 9
 * Joseph John Thomson | Chemical Heritage Foundation
 * Atomic Theory - body, used, process, law, chemical, form, energy, parts, effects, basic, part, principle, Daltons theory
 * Atomic Theory