1. Models of the Atom and the Foundations for the Periodic Chart

2. The Periodic Table of the Elements Lists All Known Elements in Rows and Columns

3. Periodic Table Terminology

4. Discover of Subatomic Particles
~1897 J.J. Thompson measured the mass of cathode rays. He found them to be 1800 times lighter than the lightest known element. These were subsequently called electrons.
~1932 The development of the mass spectrometer showed integer variations of mass of particles.
The ratio of charge to mass determined the deflection of an ionized particle in a magnetic field.
It was determined that a “+” charged particle accounted for the deflection. This was the proton.
The integer mass differences unaffected by the magnetic field had to be uncharged particles of mass equal to that of the proton. This was the neutron

5. The Structure of the Atom
Having the particles, the question of where were they had to be answered. J.J. Thompson initially proposed the “Plum Pudding” model where the atomic mass was distributed evenly through the atom.

6. Rutherford’s Gold Foil Experiment
Rutherford passed alpha particles through an extremely thin gold foil. He found most passed through but occasionally one would be deflected back.
Rutherford Conclusions: All of the mass of the atom is concentrated at the center or “nucleus”.

7. Schematic Magnified Cross-section of an Atom

8. Atomic Particle Mass and Change

9. Color and Energy and Visible Light Form a Continuous Spectrum

10. Quantum Model and the Failure of Classical Physics
Around the early 1900’s, many observations were unable to be explained using classical physics
Black body radation
Diffraction of electrons
Line Spectra
Cumulated observation necessitated a new mechanics to explain them. The result was the birth of Quantum Mechanics

11. (a) Light From a Hydrogen Lamp When Dispersed by a Prism is Split into its Components (b) The Emission Spectrum of Hydrogen Consists of Just Four Colors of Visible Light: Red, Green, Cyan, and Violet (Magenta)

12. (a) We Can View The Restricted Energy of an Atom as Steps on a Ladder, To the Left of the Ladder Is an Energy-level Schematic for the Steps (b) The Line Spectrum Relates to the Difference Between the Positions of the Steps, Transition Energies for Five Transitions Ending on Level B are Shown Here as a Line Spectrum Below the Energy-level Schematic

13. (a) Bohr's Model Shows the Electron Increasingly Far From the Nucleus in Higher-energy Orbits (b) The Energy of the Electron is Shown in this Energy-level Diagram

14. 1927 Solvay Conference

15. In the Oscillation of a Drumhead with No Friction, the Drumhead Cycles Indefinitely from a Crest to Flat to a Trough, and Back Again

16. Vibrating Drumhead (You-Tube) mp4
Four Successively Higher Energy Modes of a Drum Shown as Surface Plots and Contour Plots, Contour Plots are Similar to Maps with Elevation Lines
Vibrating Drumhead (You-Tube) mp4

17. Image of a Copper Surface with a Ring of 48 Iron Atoms, Taken with a Scanning Tunneling Microscope (STM)

18. Image of a Copper Surface with a Ring of 48 Iron Atoms, Taken with a Scanning Tunneling Microscope (STM)

19. Images of Organic Rings using STM
World’s Smallest Movie

20. IBM Logo
World’s Smallest Movie

21. An “S” Orbital Is Spherically Symmetric

22. (a) The 1s Orbital is the Lowest Energy, n=1, State of the Electron (b) The Spherical Surface has been Cut by a Contour to Show the Space-filling Nature of the 1s Electron Wave (c) Looking Down on the Electron Contour Plot Clarifies the Circular Symmetry of the Electron Density (d) A Plot of the Amplitude of the Wave as a Function of the Distance from the Center of the Sphere Illustrates the Exponential Drop in Density with Distance Away from the Nucleus

23. The First Excited State of the Electron has One Node, When the Node Is a Spherical Node, the State Consists of Two Large-amplitude Spheres and Is Called a 2s Orbital. But what are we to make of the “-” areas? What does this mean?

24. The wave function must have meaningful values to be representing a real particle. Therefore by the “Copenhagen” interpretation, the square of the wave function represents the probability of electron location

25. The Node of an Electron Orbital Can Be a Plane that Cuts Through the Center of the Atom

26. The Three p Orbitals Illustrated by the Bounding Surface that Contains 90% of the Electron Wave, Orbitals are Labeled According to their Direction

27. (a) A px Orbital Shown with a Slicing Surface in the x-z Plane (b) The Contour Map Shows the Node in the y-z Plane (c ) The py and pz Orbitals are Similar, with Lobes and Nodes Rotated 90 Degrees

28. Orbitals are represented in Spherical Coordinates

29. P-orbital equations
Problem 2.85 asks you to show that when the squares of the probabilities are added, it results in a sphere of probability

30. The Five 3d Orbitals. The Turquoise and Yellow Lobes are Crests and Troughs, Respectively. The Labels for These Orbitals Reflect the Directions in which the Quadratic Function has a Maximum Value

31. d-orbital equations
Problem 2.86 asks you to show that when the squares of the probabilities are added, it results in a sphere of probability

32. A Plane Slicing Through One of the d Orbitals

33. Four Quantum Numbers Indicate the Electron Orbital and Spin

34. Electron Shielding and Energy Levels
(a) Energy Levels in Hydrogen Depend Only on the Shell or Principal Quantum Number, n . (b) In Multi-electron Atoms, as Electrons Occupy Orbitals Nearer to the Nucleus, Outer Electrons are Shielded from the Nuclear Charge

35. Ionization Energies Example: Consider the Lithium atom.
Ionization Energy is the energy required to remove an electron from an atom or an ion.
IE’s are greatly affected by the effective nuclear charge experienced by an electron which is a combination of electron shielding and electron repulsion.
The ability to remove electrons is critical to the formation of ions, or the conductivity of the metal among other many physical properties.
Example: Consider the Lithium atom.

36. The Ionization Energy of the Three Electrons in the Lithium Atom Demonstrate the Shielding of the Outer-shell Electron by the Two Inner-shell Electrons

37. Ionization Energy Jumps After the First Ionization in Group 1, After the Second Ionization in Group 2, and After the Third Ionization in Group 13

38. Electron Filling Occurs in Blocks in the Periodic Table