CHEMISTRY

 75-Rhenium

-The chemical symbol : Re -The origin of the name: From Rhines provinces of Germany Where was the element discovered?: gadolinite, molybdenite
 * Main Properties
 * Who discovered the element?: Walter Noddack

[Xe] 4f14 5d5 6s2
 * Total electron configuration

-Atomic Radius :137 pm -ionization energy :760 kJ/mole -Electron Affinity :14 kJ/mole -Electronegativity: 1.9
 * Periodic Properties:

- It is widely used as filaments for mass spectrographs and ion gauges. Rhenium-molybdenum alloys are superconductive at 10 K. Rhenium is also used as an electrical contact material because it has good wear resistance and withstands arc corrosion. Thermocouples made of Re-W are used for measuring temperatures up to 2200C, and rhenium wire is used in photoflash lamps for photography.
 * Use of the element:

-In 1928 rhenium cost $10,000/g. The price today is about $250/troy oz.
 * Economic part:

Reviewed by GL

=Quarks .= ===Quarks are smallest particles that can posse both electric charges .When they combine they made a gropu of 3 or 2 made a baryons,Protons and Neutrons are made of 3 quarks both. They have differents species. like up and down quarks .The heavier quarks aren't found in nature and are found in particle accelerators..Each of the six quarks can have three diffrerents colors, and the masses should not be taken soo seriously. because the can change,The fist model of a quark was postulated independently by Murray Gell - Mann and George Zweig in 1964. Quarks have lots of properties like colors masses spin, and electric charge. For every different quark exist antiquarks that can be differ from the quarks because they have some different properties and also the charge can be opposite===

Number || S || C || B || T || Mass* ||
 * Quark || Symbol || Spin || Charge || Baryon
 * [|Up] || U || 1/2 || +2/3 || 1/3 || 0 || 0 || 0 || 0 || 360 MeV ||
 * [|Down] || D || 1/2 || -1/3 || 1/3 || 0 || 0 || 0 || 0 || 360 MeV ||
 * [|Charm] || C || 1/2 || +2/3 || 1/3 || 0 || +1 || 0 || 0 || 1500 MeV ||
 * [|Strange] || S || 1/2 || -1/3 || 1/3 || -1 || 0 || 0 || 0 || 540 MeV ||
 * [|Top] || T || 1/2 || +2/3 || 1/3 || 0 || 0 || 0 || +1 || 174 GeV ||
 * [|Bottom] || B || 1/2 || -1/3 || 1/3 || 0 || 0 || -1 || 0 || 5 GeV ||

media type="youtube" key="SMgi2j9Ks9k" height="344" width="425" in this video they explain us about how de scientist knows about the quarks aif they don't see they and how are they.

http://hyperphysics.phy-astr.gsu.edu/hbase/particles/quark.html http://en.wikipedia.org/wiki/Quark http://www.physlink.com/Education/AskExperts/ae134.cfm?CFID=15981990&CFTOKEN=39413682