1. Descriptive Inorganic Chemistry Chem 241
11:30 – 12:45 T, Th
Bill Vining

16. Inorganic Chemistry One of the three Descriptive Chemistries:
Biochemistry
Inorganic Chemistry
Theoretical and Practical Chemistries:
Physical Chemistry
Analytical Chemistry

17. Inorganic Chemistry: Chemistry for the rest of the elements.

18. Inorganic Chemistry Transition metal chemistry:
Metal-ligand complexes
Main group and metal-based materials science

19. Descriptive Inorganic Chemistry Chapter 2: Figure 2.2
© 2009 W.H. Freeman

20. First Assignment:
Find the best periodic
table website. Bring
URL and list of why you
think it is the best (and
any drawbacks).
Hand in paper at start
of class Friday.

21. Official Stuff
Course Website:
Syllabus

22. First Topic Where do all these elements come from? How are they made?

23. Descriptive Inorganic Chemistry Chapter 2: Figure 2.6
© 2009 W.H. Freeman

24. What aspects of this should we explain?

25. What will our explanations depend on?
Thermodynamics: relative stability
Kinetics: rate and mechanism

26. General Decrease in Abundance with Atomic Number

27. Even > Odd

28. Peak at Fe

29. Peak at Pb

30. Trough at Be

31. Missing Tc and Pm and Above N = 83

32. Nuclear equations

34. Nucleosynthesis of the Elements
Why does this happen
only in stars?
Hydrogen Burning
1H + 1H  2H + e+ + ve­
2H + 1H  3He + 
3He + 3He  4He +21H
41H  4He + 2e+ + 2ve

35. Nucleosynthesis of the Elements
CNO Catalytic Cycle for Hydrogen Burning
Greenwood and Earnshaw, Chemistry
of the Elements, 2nd Ed.

36. Helium Burning 4He +4He  8Be 8Be + 4He  12C*  12C + 
Is this easier or
harder than hydrogen
burning?

37. Carbon Burning, etc. 12C + 4He  16O +  16O + 4He  20Ne + 
20Ne + 4He  24Mg + 
12C + 12C  24Mg + 
12C + 12C  23Na + 1H
12C + 12C  20Ne + 4He
Go back to initial
Questions. Can we
answer any?

38. The -Process 20Ne +   16O + 4He 20Ne + 4He  24Mg + 
2 20Ne  16O + 24Mg + 
40Ca + 4He  44Ti* + 
44Ti* + e-  44Sc* + v+
44Sc*  44Ca + + + v+
44Ca + 4He  48Ti + 

39. Neutron Capture-Beta Decay

40. Neutron Capture-Beta Decay: r- vs. s-process
s-process: neutron capture is slower than beta decay, forming nuclei lighter than the lightest unstable isotope
The slower the absorption of n’s, the more abundant the element
(Y-89 and Zr-90, Ba-138 and Ce-140, Pb-208 and Bi-209) have #n = magic numbers 50, 82, and 126.
r-process (during a supernova): neutron capture is very rapid, forming nuclei with many more neutrons than the lightest stable isotope

42. Greenwood and Earnshaw, Chemistry
of the Elements, 2nd Ed.

43. Greenwood and Earnshaw, Chemistry
of the Elements, 2nd Ed.