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

2. Visible Spectroscopy

3. 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

4. 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)

5. Here’s what a probability density looks like… (A bit simplified) …but what does it mean?

6. 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, … )

8. 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

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

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

11. NODES- Where electrons don’t go Spherical Nodes

12. Hydrogen

13. You too can play with hydrogen… http://homepages.ius.edu/kforinas/physlets/quantum/hydrogen.html

14. 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

15. Quantum Numbers and Orbitals

16. 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

17. Orbital Filling Order