AndrewM

Assignment #1 - Intro to Wikispaces and the Atom (10pts)

Introduction to the Atom
First, we'll need to create our own page by clicking on the "New Page" button in the upper left corner of the page. Name the page after yourself, including your first name and at least your last initial; such as "John's Page" or "Melissa and Alison's Page" or simply "John S.". Once you've created your page, you need to collect information on the Atom.

//**MAKE SURE YOU ADD A LINK TO THE PAGE WHERE YOU FOUND YOUR INFORMATION OR YOU WON'T GET THE POINTS!!!**//

For a bonus point:
 * 1) History of the Atom (5pts)
 * 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.

John Dalton september 6th 1766-july 27 1844.

He was born in Eaglesfield in Cumberland, England. He died in Manchester, England at age 77. He is a known chemist, meteorologist, and physist. He is also famous for pioneering the "atom theory."


 * Scientists and Experiments**

Some recent experiments include:

Hahn, Strassman || Conducted experiments verifying that heavy elements capture neutrons and form unstable products which undergo fission. This process ejects more neutrons continuing the fission chain reaction. ||
 * || [|Isaac Newton] || Proposed a mechanical universe with small solid masses in motion. ||
 * 1803 || [|John Dalton] || Proposed an "atomic theory" with spherical solid atoms based upon measurable properties of mass. ||
 * 1832 || [|Michael Faraday] || Studied the effect of electricity on solutions, coined term "electrolysis" as a splitting of molecules with electricity, developed laws of electrolysis. Faraday himself was not a proponent of atomism. ||
 * 1859 || J. Plucker || Built one of the first gas discharge tubes ("cathode ray tube"). ||
 * 1869 || [|Dmitri Mendeleeff] || Arranged elements into 7 groups with similar properties. He discovered that the properties of elements "were periodic functions of the their atomic weights". This became known as the Periodic Law. ||
 * 1873 || [|James Clerk Maxwell] || Proposed electric and magnetic fields filled the void. ||
 * 1874 || [|G.J. Stoney] || Proposed that electricity was made of discrete negative particles he called "[|electrons]". (Link to info on electrons) ||
 * 1879 || [|Sir William Crookes] || Discovered cathode rays had the following properties: travel in straight lines from the cathode; cause glass to fluoresce; impart a negative charge to objects they strike; are deflected by electric fields and magnets to suggest a negative charge; cause pinwheels in their path to spin indicating they have mass. ||
 * 1886 || E. Goldstein || Used a CRT to study "canal rays" which had electrical and magnetic properties opposite of an electron. ||
 * 1895 || [|Wilhelm Roentgen] || Using a CRT he observed that nearby chemicals glowed. Further experiments found very penetrating rays coming from the CRT that were not deflected by a magnetic field. He named them "X-rays". ||
 * 1896 || [|Henri Becquerel] || While studying the effect of x-rays on photographic film, he discovered some chemicals spontaneously decompose and give off very pentrating rays. ||
 * 1897 || [|J.J. Thomson] || Used a [|CRT] to experimentally determine the charge to mass ratio [|(e/m)] of an electron =1.759 x 108 coulombs/gram. ||
 * 1897 || [|J.J. Thomson] || Studied "canal rays" and found they were associated with the proton H+ . ||
 * 1898 || [|Rutherford] || Studied radiations emitted from uranium and thorium and named them //alpha// and //beta.// ||
 * 1898 || [|Marie Sklodowska Curie] || Studied uranium and thorium and called their spontaneous decay process "radioactivity". She and her husband Pierre also discovered the radioactive elements polonium and radium. ||
 * 1900 || [|Soddy] || Observed spontaneous disintegration of radioactive elements into variants he called "isotopes" or totally new elements, discovered "half-life", made initial calculations on energy released during decay. ||
 * 1900 || Max Planck || used the idea of quanta (discrete units of energy) to explain hot glowing matter. ||
 * 1903 || Nagaoka || Postulated a "Saturnian" model of the atom with flat rings of electrons revolving around a positively charged particle. ||
 * 1904 || Abegg || Discovered that inert gases had a stable electron configuration which lead to there chemical inactivity. ||
 * 1906 || [|Hans Geiger] || Developed an electrical device to "click" when hit with alpha particles. ||
 * 1909 || [|R.A. Millikan] || Oil drop experiment determined the charge (e=1.602 x 10-19 coulomb) and the mass (m = 9.11 x 10-28 gram) of an electron. ||
 * 1911 || [|Ernest Rutherford] || Using alpha particles as atomic bullets, probed the atoms in a piece of thin (0.00006 cm) [|gold foil]. He established that the nucleus was: very dense,very small and positively charged. He also assumed that the electrons were located outside the nucleus. ||
 * 1914 || [|H.G.J. Moseley] || Using x-ray tubes, determined the charges on the nuclei of most atoms. He wrote"The atomic number of an element is equal to the number of protons in the nucleus". This work was used to reorganize the periodic table based upon atomic number instead of atomic mass. ||
 * 1919 || Aston || Discovered the existence of isotopes through the use of a mass spectrograph. ||
 * 1922 || [|Niels Bohr] || Developed an explanation of atomic structure that underlies regularities of the periodic table of elements. His atomic model had atoms built up of sucessive orbital shells of electrons. ||
 * 1923 || [|de Broglie] || Discovered that electrons had a dual nature-similar to both particles and waves. Particle/wave duality. Supported Einstein. ||
 * 1927 || [|Heisenberg] || Described atoms by means of formula connected to the frequencies of spectral lines. Proposed Principle of Indeterminancy - you can not know both the position and velocity of a particle. ||
 * 1929 || [|Cockcroft / Walton] || Built an early linear accelerator and bombarded lithium with protons to produce //alpha particles// ||
 * 1930 || [|Schrodinger] || Viewed electrons as continuous clouds and introduced "wave mechanics" as a mathematical model of the atom. ||
 * 1930 || Paul Dirac || Proposed //anti-particles//. Anderson discovered the anti-electron (positron) in 1932 and Segre/Chamberlain detected the anti-proton in 1955. ||
 * 1932 || James Chadwick || Using alpha particles discovered a neutral atomic particle with a mass close to a proton. Thus was discovered the neutron. ||
 * 1938 || [|Lise Meitner],
 * 1941 - 51 || [|Glenn Seaborg] || Synthesized 6 transuranium elements and suggested a change in the layout of the periodic table. ||
 * 1942 || [|Enrico Fermi] || Conducted the first controlled chain reaction releasing energy from the atoms nucleus. ||


 * Structure of an Atom**

What is an atom? Atoms are the building blocks of matter. The word ‘atom’ was originally meant to indicate the smallest indivisible part of matter. However, research revealed that an atom was in fact not the indivisible unit of matter and that it consisted of other particles. They came to be known as the subatomic particles. [|What makes up an atom]? What are the different parts of an atom? Let us find out.

The central portion of an atom is known as the atomic nucleus. It consists of protons, which carry positive charge and neutrons, which carry no electric charge. The negatively charged electrons orbit the atomic nucleus. The protons and neutrons in an atomic nucleus contribute to the atomic mass. However, the electrons floating in the region around the nucleus are extremely lightweight subatomic particles.

If protons are positively charged particles and electrons are negatively charged, how does an atom not have electric charge? Do the neutrons neutralize the electric charge of an atom? Imagine, if atoms were to bear electric charge, we would be getting electrical shocks on touching anything around us. As atoms make up matter and matter makes up the universe, we would probably have to thrive in an electrically charged world! But thanks to the equal number of protons and electrons in an atom, matter does not possess electric charge. Yes, every atom has an equal number of protons and electrons. This nullifies the electric charge, thus making atoms electrically neutral.

Atoms get together to form molecules. When atoms of different elements come together, compound molecules are formed. As you might know, there are two types of compounds, ionic and covalent. The ions of ionic compounds are bound together due to the electrostatic forces between oppositely charged bodies. When atoms share pairs of electrons to form chemical bonds, they are known as covalent compounds. [|Chemical reactions] between atoms of different elements result in the formation of complexly structured compounds. Being the fundamental units of matter, it won’t be an exaggeration to say that atoms are omnipresent; they are within you, around you and everywhere. Different parts of an atom include: Protons, Neutrons and Electrons. Proton=positive charge Neutron=neutral charge Electron= negative charge

The reason that atoms of different elements are different is because the have different numbers of protons.