6.4 The Wave Behavior of Matter
Louis de Broglie (1892-1987)
• proposed if radiant energy (under appropriate conditions) could behave as a stream of particles and exhibit properties of waveà
λ=
h = Planck’s constant 6.626 x 10-34 J/s m = mass v = velocity mv = momentum
PRACTICE: What is the wavelength of an electron moving with a speed of 5.97 x 106 m/s? mass of e- =9.11 x 10-31 kg. 1 J =1 kg m2/s2
Wave properties of e- demonstrated experimentally…
Electron diffractionà
• as electrons are passed though a ______they are diffracted
• stream of electrons exhibits similar kind of ______behavior as EM radiation
• technique used in ______microscope to obtain images at atomic scale (3,000,000 x magnification)
The Uncertainty Principle
• If an e- exhibits wave properties, can we calculate the position, direction of motion, and speed at any time???
• Werner Heisenberg (1901- 1976)
• Uncertainty Principleà
RESULT
De Broglie’s hypo and Heisenberg’s Uncertainty Principle set stage for new approach to atomic structureà model that describes ______of e- while describing probabilities of ______
6.5 Quantum Mechanics and Atomic Orbitals
Erwin Schrodinger (1887-1961)
• Austrian physicist
• ______à incorporates wave and particle behavior of e- = quantum mechanics or wave mechanics
u Solving equation lead toà Wave functions- def.
u ex: Ψ Greek letter psi
u Ψ2 à provides info about e- location when in allowed energy state =
Orbitals def:
Quantum Numbers
1. Principle Quantum Number (n)
· Indicates
· as n increases = orbital becomes ______à e- spend more time farther from nucleus
· as n increases =
· n determines the number of ______within the principle energy level
2. Angular Momentum Number (l)
· l =
·
3. Magnetic Quantum Number (ml)
· describes
· equal to
· ex: l = 3; then ml =
• Electron shell:
• Subshell:
Ground State:
Excited State:
6.6 Representation of Orbitals
S orbital:
Radial Probability Densityà
node:
p Orbital
d= four leaf clover shape orbitals
•
• ml=
f= complicated shape
•
• ml =