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Download Atomic structure - Mrs. Wernau's Pre-AP Chemistry
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S.MORRIS 2006 Timeline of Atomic Theory 450 BC 1800’s ________________________________________________________ _ Democritus: http://greatphilosophers.suite101.com/article.cfm/democritus_and_at omistic_philosophy http://www.fortbend.k12.tx.us/campuses/documents/Teach er/2009/teacher_20090928_0656.doc matter was made of “atoms” Dalton: http://www.iun.edu/~cpanhd/C101webnotes/co mposition/dalton.html http://www.fortbend.k12.tx.us/campuses/docu ments/Teacher/2009/teacher_20090928_0656_ 2.doc proposed 4 components to an Atomic Theory. Atomic Theory 1897-1920 ___________________________________ Thomson Planck http://highered.mcgrawhill.com/sites/0072512644/student_vi ew0/chapter2/animations_center.htm l http://web2.uwindsor.ca/c ourses/physics/high_sch ools/2005/Photoelectric_e ffect/planck.html negative charge in the atom 1897 Quanta 1901 Millikan http://highered.mcgrawhill.com/sites/0072512644/stude nt_view0/chapter2/animations_c enter.html charge on e1910 Rutherford http://www.mhhe.com/phys sci/chemistry/essentialche mistry/flash/ruther14.swf nucleus 1911 Bohr http://www.wwnorton.com/college/ch emistry/gilbert/tutorials/ch3.htm#top http://www.chempractice.com/drills/j ava_Bohr.php quantum model 1913 Contributions to Modern Atomic Theory De Broglie Wave Gell-Mann nature of Heisenberg Quarks matter ___________________________________ e- is a wave 1962 and a particle 1924 __ 1926 Schrodinger Chadwick e- orbits as a neutron wave 1926 1932 HISTORY OF THE ATOM 460 BC Democritus develops the idea of atoms he pounded up materials in his pestle and mortar until he had reduced them to smaller and smaller particles which he called ATOMA (greek for indivisible) HISTORY OF THE ATOM 1808 John Dalton suggested that all matter was made up of tiny spheres that were able to bounce around with perfect elasticity and called them ATOMS Dalton’s Atomic Theory • All matter consists of tiny particles. • Atoms are indestructible and unchangeable (Has been modified with recent discoveries in nuclear chemistry) • Elements are characterized by the mass of their atoms. • When elements react, their atoms combine in simple, whole-number ratios. Their atoms sometimes combine in more than one simple Laws that came from Dalton’s Atomic Theory • Law of Conservation of Mass (mass cannot be created or destroyed) • Law of Definite Composition/ Law of Proportions • Law of Multiple Proportions HISTORY OF THE ATOM 1898 Joseph John Thompson found that atoms could sometimes eject a far smaller negative particle which he called an ELECTRON HISTORY OF THE ATOM 1904 Thomson develops the idea that an atom was made up of electrons scattered unevenly within an elastic sphere surrounded by a soup of positive charge to balance the electron's charge like plums surrounded by pudding. PLUM PUDDING MODEL Thomson’s Experiment with the Cathode Ray Tube http://highered.mcgrawhill.com/sites/0072512644/student_view0/c hapter2/animations_center.html# Planck and the Quanta • Click to read about Planck and his experiments and ideas • http://web2.uwindsor.ca/courses/physics/hi gh_schools/2005/Photoelectric_effect/plan ck.html Millikan 1910 • http://highered.mcgrawhill.com/sites/0072512644/student_view 0/chapter2/animations_center.html • Charge on an electron HISTORY OF THE ATOM 1910 Ernest Rutherford: The Gold Foil Experiment oversaw Geiger and Marsden carrying out his famous experiment. they fired Helium nuclei at a piece of gold foil which was only a few atoms thick. they found that although most of them passed through. About 1 in 10,000 hit HISTORY OF THE ATOM gold foil helium nuclei helium nuclei They found that while most of the helium nuclei passed through the foil, a small number were deflected and, to their surprise, some helium nuclei bounced straight back. This indicated a small dense positively charged center. HISTORY OF THE ATOM Rutherford’s new evidence allowed him to propose a more detailed model with a central nucleus. He suggested that the positive charge was all in a central nucleus. With this holding the electrons in place by electrical attraction. The electrons occupied most of the space of an atom/ makes up most of the volume of an atom. However, this was not the end of the story. HISTORY OF THE ATOM 1913 Niels Bohr studied under Rutherford at the Victoria University in Manchester. Bohr refined Rutherford's idea by adding that the electrons were in orbits. Rather like planets orbiting the sun. With each orbit only able to contain a set number of electrons. Bohr’s Atom electrons in orbits nucleus HELIUM ATOM Shell proton + - N N + electron What do these particles consist of? - neutron More Practice with Bohr Model http://www.chempractice.com/drills/java _Bohr.php Parts of the atom Particles of the Atom to date: • Nucleus – Protons = p+ = 3 quarks Held together by 0 – Neutrons= n = 3 quarks a force called : Gluon • Electron Cloud – Electrons =e- (particle/wave) Types of Quarks Determine Charge http://nobelprize.org/educational_games/physics/matter/1.html Quarks = up (+2/3) and down (-1/3) p+ = 2ups and 1 down up +2 +2 -1 = +1 3 3 3 n0 = 2 down and 1 -1 3 -1 3 +2 = 0 3 Gluon forces between quarks This powerpoint was kindly donated to www.worldofteaching.com Modified by Mrs. Wernau with material from Mrs. Echter and Mrs. Paul. http://www.worldofteaching.com is home to over a thousand powerpoints submitted by teachers. This is a completely free site and requires no registration. Please visit and I hope it will help in your teaching.
