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Section 1: Structure of the Atom PROPERTIES OF THE ATOM & THE PERIODIC TABLE

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Elements on the periodic table are represented by symbols. Chemical symbols consist of one capital letter or a capital letter plus one or two lowercase letters. The symbol for silver is Ag. Silvers Latin name is Argentum. The symbol for gold is Au. Golds Latin name is Aurum. Plumbium is leads Latin name. Leads symbol is Pb. A subscript to the right of a symbol indicates the number of atoms of that particular element present in a compound. SCIENTIFIC SHORTHAND

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An atom is the smallest piece of matter that still keeps the properties of the element. The element silver is only silver atoms, uranium atoms are only uranium atoms. Atoms are different from one another because of the number of PROTONS they have. Silver always has 47 protons Uranium always has 92 protons. ATOMIC COMPONENTS PARTS OF THE ATOM

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The nucleus is the center of the atom. It is made up of: protons, with a positive electrical charge (+), neutrons with a neutral charge (no charge). The electrons are found outside the nucleus in what is called a cloud. Electrons have a negative electrical charge (-). Electrons are approximately 1/10,000 the size of a proton or neutron. THE PARTS...

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Smaller particles make up protons and neutrons. These are called quarks. There are six kinds of quarks - up quarks, down quarks, strange quarks, charm quarks, bottom quarks, and top quarks. Their names don't really mean anything, just that they are different kinds of quarks. EVEN SMALLER PARTS...

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Quarks were hard to find. Particles had to be accelerated into collisions with great force and speed. The Tevatron at the Fermi Accelerator in Illinois was used for these experiments. It is about 6.4 km in circumference and uses electric and magentic fields to accelerate, focus, and collide particles. Particles are detected using computers and other particles. MORE ON QUARKS...

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In order to understand their calculations, physicists assigned the quarks fractional electrical charges of 2/3 and -1/3. Such charges had never been observed before. Quarks are never observed by themselves, and so initially these quarks were regarded as mathematical fiction. Experiments have since convinced physicists that not only do quarks exist, but there are six of them, not three.

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The top quark was discovered last. It is the most massive quark. It had been predicted for a long time but had never been observed successfully until 1995. A team of nearly 450 scientists helped to find it. EVEN SMALLER PARTS...

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Tevatron Collider was shut down September 30, 2011 FERMILAB...

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Old bubble chamber at Fermi Used to capture images of the tracks of subatomic partices after collisions. BUBBLE CHAMBERS...

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http://en.wikipedia.org/wiki/List_of_accelerators_ in_particle_physicshttp://en.wikipedia.org/wiki/List_of_accelerators_ in_particle_physics ACCELERATORS IN HISTORY

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Large Hadron Collider: http://www.telegraph.co.uk/science/large- hadron-collider/8675126/Spectacular-images- from-Big-Bang-recreation.html NEW ACCELERATORS

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A proton is made of two up quarks and a down quark. A neutron is made of two down quarks and an up quark. A force called the strong nuclear force holds the quarks together.strong nuclear force Up quarks have a little bit of mass, but most of the mass of a proton comes from the strong nuclear force itself, rather than from the quarks.mass MORE

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Leptons, fermions, muons, neutrinos, hadrons, bosons http://dsc.discovery.com/tv- shows/curiosity/topics/subatomic-particles-in-a- nutshell.htmhttp://dsc.discovery.com/tv- shows/curiosity/topics/subatomic-particles-in-a- nutshell.htm PARTICLES NAMES WE ARENT GOING TO TALK ABOUT (MUCH) PARTICLES NAMES WE ARENT GOING TO TALK ABOUT (MUCH)

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JUST HOW SMALL IS AN ATOM? https://www.youtube.com/watch?v=yQP4U JhNn0I&feature=player_embeddedhttps://www.youtube.com/watch?v=yQP4U JhNn0I&feature=player_embedded There are about 5 sextillion atoms in a drop of water. Thats about 5,000,000,000,000,000,000,000 atoms of hydrogen and oxygen.

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USING MODELS TO UNDERSTAND Models allow you to see something that is either too large or too small, or to envision something that has not yet been built. Scaled-down models The globe The solar system Airplanes Buildings

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USING MODELS TO UNDERSTAND Scaled-up models Bacteria Other cells Atoms and compounds

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Democritus was a Greek philosopher who lived from 480 BC to 370 BC. He created a theory that argued that there are various basic elements which always existed but can be rearranged into many different forms. EARLY IDEAS OF ATOMS

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DEMOCRITUSTHE GREEK DUDE Democritus said that matter is made up of small particles Named the parts of matter atomos, which means uncuttable. Quote: By convention there is sweet, by convention there is bitterness, by convention hot and cold, by convention color; but in reality there are only atoms and the void.

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ARISTOTLE ARGUED Another Greek philosopher named Aristotle argued that matter was the same throughout and NOT composed of small particles. He believed that every thing was made of its own type of matter, so, in essence, a table was made of table matter. This idea actually stuck for almost 2,000 yearsover Democrituss idea.

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JOHN DALTON Lived 6 September 1766 27 July 1844 Was a schoolteacher and scientist in England Looked at Democrituss ideas and also thought atoms were tiny solid masses that make up matter. Dalton first published his theories on atoms in 1808 in a small book titled A New System of Chemical Philosophy. The book had an enormous influence on the development of both chemistry and physics.

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JOHN DALTONS ATOMIC THEORY 1.Elements are made of tiny particles called atoms. 2. All atoms of a given element are identical. 3. The atoms of a given element are different from those of any other element. 4. Atoms of one element can combine with atoms of other elements to form chemical compounds; a given compound always has the same relative numbers of types of atoms. 5. Atoms cannot be created, divided into smaller particles, nor destroyed in the chemical process; a chemical reaction simply changes the way atoms are grouped together.

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J.J. THOMSONS DISCOVERY OF THE NEGATIVE CHARGE (ELECTRON) IN 1897 Click here for Thomson's discoveryClick here for Thomson's discovery He took Daltons spherical atoms idea and found that there is a negative charge associated with the particles. He imagined the negative particles to be like the raisins embedded in a plum pudding. I like to compare it to a blob of chocolate chip cookie dough.

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BOHRS MODEL Danish physicist Niels Bohr, 1913 Hypothesized that electrons travel in fixed orbis around the atoms nucleus In 1911 Ernest Rutherford and his student James Chadwick discovered that the nucleus contained positive protons and neutral neutrons. We use this model today to understand the basic structure of the atom Rutherford's experiment to detect the nucleus

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ELECTRON CLOUD MODEL 1926 An electron cloud is the area around the nucleus of an atom where its electrons are most likely found. The clouds diameter is 100,000 times larger than the diameter of the nucleus. Therefore, most of an atom is made up of empty space. It is not a good model to use to understand electron placement and transfers, however.

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ELECTRON CLOUD MODEL 1926

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ORBITALS OF ATOMS The Electron Cloud Model is alternately called the Atomic Orbital Model. Electrons actually travel more in orbitals. Orbitals give a more accurate placement of electrons. Some periodic tables state the electron orbitals. They are shown at the right.

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ORBITALS OF ATOMS