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

2. Copyright © Houghton Mifflin Company. All rights reserved.2 | 2 The Periodic Table of the Elements Lists All Known Elements in Rows and Columns

3. Copyright © Houghton Mifflin Company. All rights reserved.2 | 3 Periodic Table Terminology

4. Copyright © Houghton Mifflin Company. All rights reserved.2 | 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. Copyright © Houghton Mifflin Company. All rights reserved.2 | 5 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. The Structure of the Atom

6. Copyright © Houghton Mifflin Company. All rights reserved.2 | 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. Copyright © Houghton Mifflin Company. All rights reserved.2 | 7 Schematic Magnified Cross-section of an Atom

8. Copyright © Houghton Mifflin Company. All rights reserved.2 | 8 Atomic Particle Mass and Change

9. Copyright © Houghton Mifflin Company. All rights reserved.2 | 9 Color and Energy and Visible Light Form a Continuous Spectrum

10. Copyright © Houghton Mifflin Company. All rights reserved.2 | 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. Copyright © Houghton Mifflin Company. All rights reserved.2 | 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. Copyright © Houghton Mifflin Company. All rights reserved.2 | 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. Copyright © Houghton Mifflin Company. All rights reserved.2 | 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. Copyright © Houghton Mifflin Company. All rights reserved.2 | 14 1927 Solvay Conference

15. Copyright © Houghton Mifflin Company. All rights reserved.2 | 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. Copyright © Houghton Mifflin Company. All rights reserved.2 | 16 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 DrumheadVibrating Drumhead(You-Tube)mp4mp4

17. Copyright © Houghton Mifflin Company. All rights reserved.2 | 17 Image of a Copper Surface with a Ring of 48 Iron Atoms, Taken with a Scanning Tunneling Microscope (STM) IBM Research Center IBM Research Center

18. Copyright © Houghton Mifflin Company. All rights reserved.2 | 18 An s Orbital Is Spherically Symmetric

19. Copyright © Houghton Mifflin Company. All rights reserved.2 | 19 (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

20. Copyright © Houghton Mifflin Company. All rights reserved.2 | 20 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

21. Copyright © Houghton Mifflin Company. All rights reserved.2 | 21 The Node of an Electron Orbital Can Be a Plane that Cuts Through the Center of the Atom

22. Copyright © Houghton Mifflin Company. All rights reserved.2 | 22 The Three p Orbitals Illustrated by the Bounding Surface that Contains 90% of the Electron Wave, Orbitals are Labeled According to their Direction

23. Copyright © Houghton Mifflin Company. All rights reserved.2 | 23 (a) A p x 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 p y and p z Orbitals are Similar, with Lobes and Nodes Rotated 90 Degrees

24. Copyright © Houghton Mifflin Company. All rights reserved.2 | 24 Orbitals are represented in Spherical Coordinates

25. Copyright © Houghton Mifflin Company. All rights reserved.2 | 25 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

26. Copyright © Houghton Mifflin Company. All rights reserved.2 | 26 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

27. Copyright © Houghton Mifflin Company. All rights reserved.2 | 27 A Plan Slicing Through One of the d Orbitals

28. Copyright © Houghton Mifflin Company. All rights reserved.2 | 28 Four Quantum Numbers Indicate the Electron Orbital and Spin

29. Copyright © Houghton Mifflin Company. All rights reserved.2 | 29 (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 Electron Shielding and Energy Levels

30. Copyright © Houghton Mifflin Company. All rights reserved.2 | 30 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

31. Copyright © Houghton Mifflin Company. All rights reserved.2 | 31 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

32. Copyright © Houghton Mifflin Company. All rights reserved.2 | 32 Electron Filling Occurs in Blocks in the Periodic Table