Evidence for De Broglie Hypothesis :
Evidence for De Broglie Hypothesis Davisson and Germer showed experimentally that
electrons can, like light waves, diffract.
-Other researchers demonstrated interference with
electrons, another property of waves.
-Much of this research revealed results that matched De
Broglie’s calculated electron wavelengths.
-De Broglie won the Nobel Prize in 1929 for this concept.
Light versus Electron Diffraction :
Light versus Electron Diffraction
Electrons: Waves and Particles? :
Electrons: Waves and Particles? Big problem …. If electrons are both particles and waves, then where are they in the atom?
Werner Heisenberg: Uncertainty Principle :
Werner Heisenberg: Uncertainty Principle We can not know both the position and momentum of a particle at a given time. (1927)
Erwin Schrodinger, 1925Quantum (wave) Mechanical Model of the Atom :
Erwin Schrodinger, 1925Quantum (wave) Mechanical Model of the Atom -Developed equation (wave equation)
that treated electrons in atoms as waves.
-Only waves of specific energies provided
solutions to his equation.
-Along with Heisenberg principle, this wave
equation laid the foundation for modern
quantum theory
What Schrodinger’s Equation Means to Chemists :
What Schrodinger’s Equation Means to Chemists Electrons do not travel around the nucleus in neat orbits.
We only have a probability of finding an electron at a given
place around the nucleus.
-Electrons exist in orbitals that have three dimensional shapes.
These orbital shapes are described by the solutions to
Schrodinger’s wave equation for different energies.
-Property of orbitals can be described by 4 quantum numbers.
Four Quantum Numbers :
Four Quantum Numbers -Principal Quantum Number (n)
Main Energy Levels
-Orbital Quantum Number (l)
Shape of Orbitals, Energy Sublevels
-Magnetic Quantum Number (m)
Orientation of Orbitals, Number of Orbitals
-Spin Quantum Number
Spin on the electron +1/2 or -1/2