1. Interstudio 2
September 15, 2004

2. Interstudio 2 Outline Warm up Recap aspects of studio in first week
Atomic models
How do we see atoms today?
Atomic orbitals & electron configurations
(PT S2)
Office Hour today 4:30-5:30
Textbook?

3. Concept Question 1
Which of the following samples could be methane, CH4?  A sample that contains:
(a) 25% hydrogen by weight; 75% carbon by weight
(b) 4.0 g of H atoms and 1.0 g of C atoms
(c) 0.40 mole of H atoms and 1.0 x 1023 C atoms
(d) 0.40 mole of H2 molecules and 0.20 moles of C atoms  

4. Concept Question 2
Antoine Lavoisier, the "father of chemistry", listed lime as a chemical element in his table of 33 known elements. Which of the following observations best shows that lime cannot be an element?
Lime reacts with water, generating a large amount of heat.
Lime and carbon dioxide are produced when limestone is roasted.
When a certain soft metal is burned in oxygen, lime is produced (with no other products).
Lime melts at a temperature of 2572°C.

5. Concept Question 3
What is the approximate number of carbon atoms it would take placed next to each other to make a line that would cross this dot: • 4
200
30,000,000
6.02 x 1023

6. Groups Evaluation after first exam
Skirky (2003) in his provocatively titled "A group is its own worst enemy", highlights three types of self-defeating patterns identified by Bion in groups:
pairing off (e.g. flirtation)
the identification and vilification of external enemies (e.g. 'Microsoft' or 'management')
religious veneration (things that may not be criticized)

7. Homework Models of atom extra OWL Number/type of problem will vary
Strategy
Working with one another (know that you will be responsible individually on exam)
Random guess

8. SEA FAQs: Does the unknown have to go in one special place?
Presentation reminders (ask questions)
Evaluation

9. Lab Report Formatting Purpose Experimental Results Citations
Figures, Graphs, Tables
Purpose
Experimental
Results
Citations
Grading Rubric
How long should each section be?
What should they include?
In your own words.

10. Zhao,Y. ; Chen, Z. ; Yuan,H. ; Gao, X. ; Qu, L. ; Chai, Z. ; Xing, G
Zhao,Y.; Chen, Z.; Yuan,H.; Gao, X.; Qu, L.; Chai, Z.; Xing, G.; Yoshimoto, S.; Tsutsumi, F.; Itaya, K. “Highly Selective and Simple Synthesis of C2m-X-C2n Fullerene Dimers” J.Am. Chem. Soc , 126, –

11. Sworen, J.C.; Smith, J.A.; Berg, J.M.; Wagener, K.B. J. Am. Chem. Soc. 2004, 126, 11238-11246.

12. Fact, Law, Theory, Model What models/theories have you encountered?
Why study models, especially those that have been updated/disproven?
Why the ethics discussion?
What about Rutherford’s experiment?
All giving you situations that scientists encounter as you prepare to be a scientist.
Lead into lab reports (results)

13. How many models has the Periodic Table survived?
Thompson’s Cathode Ray tube (electricity that set them up )
Milikan
Plum pudding (Thompson)
Bohr (1913)
Quantum (modern)

14. How many models has the Periodic Table survived?
Thompson cathode ray tube ( )
(other electric charge experiments)
Plum pudding
Milikan
Bohr 1913
Quantum
Periodic table (1871)
Thompson’s Cathode Ray tube (electricity that set them up )
Milikan
Plum pudding (Thompson)
Bohr (1913)
Quantum (modern)

15. Models of Molecules
H2O

16. Seeing Atoms and Molecules
Naked eye
Optical microscope
Electron microscope

17. Electron Microscope 1930s Image ~12 atom molecule
Must be used under vacuum
Electrons waves and particles
Focused using magnets
Look at image on fluorescent screen
Shorten wavelength; increase energy; destroy sample
Images from: emscope/theorysch.html

18. SEM Images Images from: www2.ijs.si/~goran/ semmate2.html
Pollen from daisy, pollen from violet, paper
Images from: www2.ijs.si/~goran/ semmate2.html

19. STM (Scanning Tunneling Microscope) 1983
STM 1986 Nobel Laureates Heinrich Rohrer and Gerd Binnig

20. STM (Scanning Tunneling Microscope)
A tip is scanned over a surface at a distance of a few atomic diameters in a point-by-point and line-by-line fashion. At each point the tunneling current between the tip and the surface is measured. The tunneling current decreases exponentially with increasing distance and thus, through the use of a feedback loop, the vertical position of the tip can be adjusted to a constant distance from the surface.

21. STM
2. The amount of these adjustments is recorded and defines a grid of values which can be displayed as a grayscale image.
3. Instead of assigning the values to a color we can also use them to deform the grid in the direction perpendicular to the surface.
4. Now we can bring back the grayscale and paint each square according to an average of the four defining grid points.
Movement controlled by piezoelectric crystals –materials that change shape in a reproducible vay when a voltage is applied across them

22. STM images of elements and atoms
Surface must be an electrical conductor
nickel
iron on copper
copper
The Kanji characters for "atom." The literal translation is something like "original child."

23. Atomic Force Microscopy
1985
Technique can directly resolve nanoscale features: 0.2nm in Z, 1-2nm in X, Y.
Can function in air and in fluids.

24. How It Works
Laser beam is reflected off the back of the cantilever as it is raster scanned across the surface.
When tip encounters a feature on the surface, displacement of the cantilever results in displacement of the laser beam on the detector.
For example, if the tip scans across a feature projecting from the sample surface, the cantilever will deflect upwards and the resultant laser spot on the detector will be displaced lower.

25. Basic Mode 1: Contact Mode
In contact mode, the tip is constantly in touch with the sample surface.
Similar to a record player, the sample is moved underneath the tip.
The tip reads the “bumps and grooves” in the sample surface, only instead of converting these bumps and grooves into music, the AFM converts them into a topographic image.

26. Basic Mode 2: Tapping Mode
Tapping mode, or intermittent contact mode, is often used for softer samples such as polymers or biological samples.
Tip is oscillated by a piezoelectric crystal.
As the tip approaches and interacts
with the sample, the amplitude of
the oscillation is decreased.
A feedback loop measures
the reduction in amplitude,
which translates into
a topographic image.

27. Surface Characterization
TappingModeTM AFM image of disc surface
CD-R
10µm x 10 µm
Image obtained from Digital Instruments website:

28. Using AFM to Studio Programmed Cell Death (Apoptosis)
-16 min.
16 min.
48 min.
1 hr 20 min.
1 hr 52 min.
2 hrs 24 min.
Distance (µm)
Height (µm)

29. More AFM Images
Zhao,Y.; Chen, Z.; Yuan,H.; Gao, X.; Qu, L.; Chai, Z.; Xing, G.; Yoshimoto, S.; Tsutsumi, F.; Itaya, K. “Highly Selective and Simple Synthesis of C2m-X-C2n Fullerene Dimers” J.Am. Chem. Soc , 126, –

30. Need models to conceptualize what we cannot see
What is an orbital?

31. Atomic Orbitals and Electron Configurations
Periodic Trends Studio 2 (p22)
p orbitals
d orbitals
f orbitals