astro102511

# astro102511 - Astronomy October 25th 2011 Clicker Question...

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Astronomy October 25 th , 2011 Clicker Question The “ion” O +5 has a net charge of +5. How many electrons are in the “cloud” around the nucleus of O +5 ? Oxygen has an atomic number of 8. 3 electrons are in the “cloud”. Proton and electron charge are equal, but opposite Net charge = #protons - #electrons Generally, the protons are stuck in the nucleus and can't be easily removed Therefore, to change the charge of an atom, one must change the number of electrons A lot of physics boils down to how matter interacts and exchanges energy, typically on microscopic scales. The world is bizarre on the microscopic level. Consider how the energy of an object can change on the macroscopic scale: A 100 kg truck moving at 100 km/s has an easily calculated amount of kinetic energy: KE = ½ mv 2 = 5 x 10 5 Joules We can change the speed of the truck by any amount, e.g., we can increase the speed to 101 km/s, 101.5 km/s, 150 km/s, (whatever) and the kinetic energy will change (check ppt) One might think an electron on an atom would behave the same way, but it does NOT The electron bound to an atom is not simply a mass moving at any velocity. The electron is attracted to the nucleus due to its opposite charge. Therefore, one might

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## This note was uploaded on 04/04/2012 for the course ASTRON 101 taught by Professor Schneider during the Fall '08 term at UMass (Amherst).

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astro102511 - Astronomy October 25th 2011 Clicker Question...

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