1. Completing the Model of the Atom
2. Probability
a. Basic Definition
i. Limited possibility of a desired outcome
b. Electron Definition
i. Possibility of an electron being in a particular position
3. Electron Probability
a. Outgrowth of Schrödinger’s work
b. Determined by the interaction of particles within an atom
c. Gives a range of positions and shapes for electron orbits
4. De Broglie
a. Extended work of Einstein and Planc’s to matter
b. Waves could be associated with all matter
c. pl =h
d. High momentum objects have low wavelength
5. Wave-Particle Duality
a. Matter and energy can both act as waves or particles
b. Level of effect determine by size and speed of particle
i. Large particles l too small to detect
ii. Most easily detected with small fast particles
6. Electron Wavelengths
a. Orbit must be discrete multiple of l
b. Thus only certain p possible
c. Limited p’s mean only discrete energies possible
d. Movement between orbits in discrete units
7. Measuring an Electron
a. To see an object we bounce energy off it
b. Photon has momentum
c. Mass of electron small enough it is affected
d. Act of measuring electron changes it
8. Heisenberg Uncertainty Principle
a. There is always uncertainty about “p” and “x” of electron
9. Schrödinger’s Waves
a. Analyze electron as a wave
b. Developed equation to describe matter wave
c. (-(h/2p)2 /2m )s2Y/(sx2) + V(x,t)Y = i(h/2p)sYat
d. Required computers to calculate
i. No physical meaning
10. Max Born
a. Recognized physical meaning
b. Y2 is probability for finding electron at particular position and time
11. Wave-Mechanical Model (Electrons)
a. Solution of Schrödinger and Born equations produce 3-D graph, shape of orbits
b. Combination of all orbits is spherical cloud
c. Radius of cloud is Bohr radius
12. Wave-Mechanical Model (Nucleus)
a. Wave functions also apply to protons and neutrons
b. Form shells within nucleus
c. Full shells are more stable, fewer isotopes
d. 2,8,20,28,58,82,126 nucleons are most stable shells
13.
14. Quantum Model
a. Energy transferred in whole units (quantum)
b. Number of quanta radiated or absorbed determine level of electron
c. Type/Color of radiation
15. Principal Quantum Number (n)
a. Energy level of electron
b. Determines radius of cloud
c. Values from 1 to ¥, only 1 to 7 observed
d. Max e- in level in 2n2, only 32 observed
16. Azimuthal Quantum Number (l)
a. Represents momentum of electron
b. Determines shape and number of orbitals
c. Values: 0 to (n–1)
17. Azimuthal Quantum Number
a. Orbitals designated s,p,d,f (from spectrum)
b. No theoretical limit, only 4 observed
c. Number per level
i. S = 1
ii. P = 3
iii. D = 5
iv. F = 7
18. Orbitals
a. Actual path of electron
b. Each may have 2 electrons
c. Shapes
i. S: a sphere
ii. P: figure 8
iii. D: 2 intersecting figure 8's
iv. F: 3 intersecting figure 8's
19. Orbital Quantum Number (ml)
a. Determines orientation along xyz axes (figure 7.7 page 239)
b. Values from -l to +l
20. Spin Quantum Number (ms)
a. Direction of spin
b. Values + ½
c. Distinguishes between pair of electrons in an orbital
21. Pauli Exclusion Principle
a. Each electron in an aAugust 15, 2002tom is unique
b. Combinations: (max number of electrons)
i. n•l•ml•ms (7•7•15•2=1470)
22. Filling the Orbitals
a. Filled in order of energy (low to high)
b. Combination of quantum numbers determine max electrons per level
c. Each orbital holds 2 (opposite spins)
d. Total electrons = total protons for atoms
e. May be different for ions
23. Periodic Table and Electrons
a. Rows represent principle quantum number
b. Groups of columns represent azimuthal quantum number
c. Pair of columns in a group represent orbital quantum number
d. Each column of a pair is spin
24. Configuration Convention
a. Number: energy level
b. Letter: sublevel
c. Exponent: number of electrons present
25. Aufbrau Principle for Configurations
a. Arrange sublevels in order of increasing energy (transparency)
b. Begin with 1s1 (hydrogen)
i. 1 electron in “s”sublevel of level 1
c. Count across periods until all electrons used up
26. Exception to Rule
a. Half-full and full levels and sublevels are more stable
b. One electron from high level may move to lower level to make full/half-full levels or sublevels
27. Shorthand Version
a. Use symbol for previous noble gas to represent core configuration
b. Place brackets around symbol
c. Show configuration of outer level
28. Lewis Dot Diagrams
a. Show only electrons in outer level (s and p)
i. Valence electrons: involved in chemical reactions
b. Step 1:
i. Element symbol used to represent nucleus and inner levels
29. Lewis Dot Diagrams
a. Step 2:
i. From the configuration determine the number of electrons in the outer level
ii. They have the highest “n”
30. Lewis Dot Diagrams
a. Step 3:
i. Each side represents 1 orbital
ii. Dots represent electrons in orbital
iii. “s” electrons are always paired
iv. “p” electrons unpaired unless > 4