reminder: study group assignment this week lab this week electron orbitals october 26, 2009
Post on 22-Dec-2015
217 views
TRANSCRIPT
Heisenberg Uncertainty Principle
We can’t know both the exact location and the energy of a particle
For electrons => We know the energy, so we don’t know the location very well
Schrödinger’s Model of Hydrogen
Electrons act as standing waves
Wave behavior is described by a wave function: ψ Certain wave functions are allowed ψ2 describes the probability of finding the electron in
a particular spot (aka, electron density)
Here’s what a probability density looks like…
(A bit simplified)
…but what does it mean?
o-r/a2 2 = x e
Orbitals
Each wave function describes a shape = Orbital Where an electron can be found/exist Organized into main shells and subshells
Number of orbitals is different for each subshell type: s = 1 orbital p = 3 orbitals d = 5 orbitals f = 7 orbitals
Size and Energy(n=1, 2, 3, … )
Shape(s, p, d, f, … )
1s ___11
2p ___ ___ ___2s ___22
3d ___ ___ ___ ___ ___
3p ___ ___ ___3s ___
33
ENERGY
•1, 2, and 3 correspond to the major energy levels (main shells)
•At the same main shell level, a p orbital will be at a higher energy than an s orbital
4f ___ ___ ___ ___ ___ ___ ___ 4d ___ ___ ___ ___ ___ 4p ___ ___ ___
4s ___
44
Quantum # Rules
There are four different quantum numbers: n, l, ml, and ms
n, l, and ml are integers n cannot be zero l can be 0 to n-1 ml can be anything from –l to l Ms can be +½ or -½
Rules for filling orbitals
1. Pauli Exclusion PrincipleNo two electrons can have the same 4 quantum numbersAn orbital has a maximum of 2 electrons of opposite spin
2. Aufbau/Build-up PrincipleLower energy levels fill before higher energy levels
3. Hund’s RuleElectrons only pair after all orbitals at an energy level have
1 electron
4. Madelung’s RuleOrbitals fill in the order of the value of n + l