Gina+Oliveri

1. History of the Atom (5pts) For a bonus point:
 * Find out the important scientists who contributed to our current knowledge of the atom. Include:
 * A picture.
 * When they lived.
 * What they did.
 * Find out the important experiments that were used to make breakthrough discoveries.
 * Who perfomed these experiments?
 * Include years of each discovery/experiment so we can get an idea of how long this process has taken.
 * 1) Atomic Structure (5pts)
 * What are the different parts of the atom?
 * What are the different particles that make up the atom?
 * Where are they located?
 * What makes atoms of different elements different?
 * 1) Add an APPROPRIATE comment to someone's page through the discussion tab.



<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">1. **History of the Atom**

n <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">__Some important people who contributed to our current knowledge of the atom are__...

<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">- J.J. Thomson <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">- John Dalton <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">- Ernest Rutherford <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">- Niels Bohr

<span style="color: red; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">J.J. Thomson <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">In 1897, J.J. Thomson, a British scientist, discovers the electron. This led to his atomic model, in which negatively charged electrons are embedded in a sphere of positive electric charge. He was alive from 1856 to 1940, and died at the age of 84.



<span style="color: red; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">John Dalton <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">In 1803, John Dalton suggested that atoms are tiny, solid, indestructible spheres, with no internal structure. He lived from 1766 to 1844, and died at the age of 78.



<span style="color: red; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">Ernest Rutherford <span style="color: black; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">In 1911, New Zealander Ernest Rutherford stated that an atom has a dense, positively charged nucleus. Electrons move randomly in the space around the nucleus. He was alive from 1871 to 1937, and died at the age of 66.



<span style="color: red; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">Neils Bohr <span style="color: black; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">In 1913, Neils Bohr presented a model in which electrons move in spherical orbits at fixed distances from the nucleus. This is pretty much the model we accept today, but some important discoveries came after Bohr, such as the electron cloud model and the neutron.



§ __<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Important experiments that were used to make breakthrough discoveries... __ <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt 0.75in;">- In the 1800’s, __John Dalton__ performed experiments with chemicals that showed that matter seemed to consist of elementary lumpy <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt 0.75in;">particles (atoms). <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt 0.75in;">- Although he did not know about their structure, he knew that evidence pointed to something fundamental. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt 0.75in;">- In 1900, __Max Planck__, who was a professor of theoretical physics in Berlin, showed that when you vibrate atoms strong enough, you can measure <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt 0.75in;">the energy. He called these energy packets, quanta. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt 0.75in;">- In 1911, __Ernest Rutherford__ thought it would be interesting to flood atoms with alpha rays, figuring that this experiment could investigate the inside of <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt 0.75in;">an atom. He used Radium as the source of the alpha particles and shinned them onto the atoms in gold foil. Behind the foil lay a fluorescent screen in <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt 0.75in;">which he could observe the alpha’s impact. His observation was unexpected. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt 0.75in;">- Somewhere between 1896 and 1904, __Joseph John Thomson__ discovered a method for separating different kinds of atoms and molecules by the use <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt 0.75in;">of positive rays. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt 0.75in;">- In 1912, __Niels Bohr__ came up with a theory that said the electrons do not spiral into the nucleus like thought in previous years. He made two rulesthat <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt 0.75in;">describe the way atoms operate. 1: Electrons can orbit only at certain allowed distances from the nucleus. 2: Atoms radiate energy when an electron <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt 0.75in;">jumps from a higher-energy orbit to a lower-energy orbit. Also, an atom absorbs energy when an electron gets boosted from a low-energy orbit to <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt 0.75in;">a high-energy orbit.

<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt;">2. **Atomic Structure**

§ <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">The different parts of the atom… <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 0pt 59.25pt; text-indent: -0.25in;">- Protons, which are positively charged <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 0pt 59.25pt; text-indent: -0.25in;">- Electrons, which are negatively charged <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 0pt 59.25pt; text-indent: -0.25in;">- Neutrons, which have no charge <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 0pt 59.25pt; text-indent: -0.25in;">- There are two main parts to an atom: the nucleus and the area surrounding the nucleus. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 0pt 59.25pt; text-indent: -0.25in;">- In the nucleus, protons and neutrons are found <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 0pt 59.25pt; text-indent: -0.25in;">- Outside the nucleus, electrons are found moving around at different energy levels,which is called an electric cloud. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 0pt 59.25pt; text-indent: -0.25in;">- Depending on what the atom is making up, there are numerous combinations for how many of each there are. <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt 59.25pt; text-indent: -0.25in;">- Protons and neutrons, which are called nucleons when they’re found in an atomic nucleus, are further made up of even smaller subatomic particles <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0in 0in 10pt 59.25pt; text-indent: -0.25in;">called quarks



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