102atomicstructure

102atomicstructure - Atomic Structure Glenn V Lo Department of Physical Sciences Nicholls State University Brief History Dalton atom =

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
    Atomic Structure Glenn V. Lo Department of Physical Sciences Nicholls State University
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
    Brief History Dalton: atom = structureless spheres J.J. Thomson: CRT experiments led to  discovery of electrons Rutherford: alpha-scattering experiments led  to the nuclear model: Most of mass = Nucleus: protons (+) and neutrons Electrons (-) found in mostly empty space around  nucleus
Background image of page 2
    Problems Knowledge at the time suggests that nuclear  model cannot be stable.  Electrons moving  around nucleus will continually emit light (lose  energy) and eventually crash into nucleus Line spectra of atoms was “puzzling” Electromagnetic Radiation review: http://www.colorado.edu/physics/2000/quantumzone/index.html   Separating light into its components:  http://hea-www.harvard.edu/~efortin/thesis/Assets/Images/BG02FG07.JPG Excellent website on Line spectra  http://hea-www.harvard.edu/~efortin/thesis/html/Spectroscopy.shtml
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
    Bohr’s model Niels Bohr proposed the existence of stable  circular orbits for electrons: radius of n th  orbit = 52.9 n 2  pm.  (1 pm = 10 -12  m) What is the radius of the third orbit? Bohr’s model explained line spectrum for  hydrogen by assuming that: Electron in an orbit has a well-defined energy; electron in  larger orbit has higher energy. Energy is “ quantized .”   Bohr’s theory is called the “old quantum theory.”  Energy of photon produced is equal to energy released by  electron as it moves from a higher orbit to a lower orbit. Not  every color of light is observed because only some orbits are  allowed.
Background image of page 4
    Failures of Bohr model Bohr’s model only works for H atom and ions  with one electron (such as He + , Li 2+ ).  For which of the following does the Bohr model  work? B, B + , B 2+ , B 3+ , B 4+ Other experiments towards the end of the 19 th   century led to the Heisenberg Uncertainty  Principle: “ it is impossible to precisely locate  electron and know its velocity at the same  time .”  The well-defined circular orbit in Bohr’s  model is not consistent with this principle.
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
    Modern Quantum Theory Any theory to supplant Bohr’s theory must be  consistent with “energy quantization” as proposed by Bohr The Heisenberg Uncertainty Principle Modern Quantum Theory proposes a “wave 
Background image of page 6
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 06/11/2009 for the course CHEM 105 taught by Professor Wessel during the Spring '08 term at Nicholls State.

Page1 / 35

102atomicstructure - Atomic Structure Glenn V Lo Department of Physical Sciences Nicholls State University Brief History Dalton atom =

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online