REMINDER: STUDY GROUP ASSIGNMENT THIS WEEK LAB THIS WEEK ELECTRON ORBITALS October 26, 2009

Visible Spectroscopy

Heisenberg Uncertainty Principle We can’t know both the exact location and the energy of a particlethe 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 wavesstanding waves Wave behavior is described by a wave function: ψ  Certain wave functions are allowed  ψ 2 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?

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, … ) Size and Energy (n=1, 2, 3, … ) Shape (s, p, d, f, … ) Shape (s, p, d, f, … )

1s ___ 1 2p ___ ___ ___ 2s ___ 2 3d ___ ___ ___ ___ ___ 3p ___ ___ ___ 3s ___ 3 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 ___ 4

What type of orbital is this? 1. s 2. p z 3. d xy 4. d xz 10

Which type of orbital can’t exist? 1. 1p x 2. 2p x 3. 2s 4. 3d xy 10

NODES- Where electrons don’t go Spherical Nodes

Hydrogen

You too can play with hydrogen…

Quantum # Rules There are four different quantum numbers: n, l, m l, and m s  n, l, and m l are integers  n cannot be zero  l can be 0 to n-1  m l can be anything from –l to l  Ms can be +½ or -½

Quantum Numbers and Orbitals

Rules for filling orbitals 1. Pauli Exclusion Principle No two electrons can have the same 4 quantum numbers An orbital has a maximum of 2 electrons of opposite spin 2. Aufbau/Build-up Principle Lower energy levels fill before higher energy levels 3. Hund’s Rule Electrons only pair after all orbitals at an energy level have 1 electron 4. Madelung’s Rule Orbitals fill in the order of the value of n + l

Orbital Filling Order