Descriptive Inorganic Chemistry Chem 241 11:30 – 12:45 T, Th Bill Vining 436-2698 william.vining@oneonta.edu

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

Inorganic Chemistry: Chemistry for the rest of the elements.

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

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

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.

Official Stuff Course Website: http://employees.oneonta.edu/viningwj/chem241/ Syllabus

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

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

What aspects of this should we explain?

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

General Decrease in Abundance with Atomic Number

Even > Odd

Peak at Fe

Peak at Pb

Trough at Be

Missing Tc and Pm and Above N = 83

Nuclear equations

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

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

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

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?

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 + 

Neutron Capture-Beta Decay

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

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

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