1. Chemistry of Life Unit 1 – Ch 2

2. Elements of Life C, O, H, N ….96% of living matter P, S, Ca, K …. Approx 4 % of living matter Trace Element : Fe, I (I) is essential to hormone production in the human thyroid…goiter (Fe) essential for many functions (blood)…cause iron deficiency, fatigue, exhaustion, ADD etc b/c it carries Oxygen

3. Atoms & Molecules Define Matter, Element, Compound Atom: nucleus, protons, neutrons, electrons, orbitals Atomic # - # protons Mass # - p + + n 0 Dalton 1.7 x 10 -24 g …mass of p + and n 0 Atomic Wt more precise

4. Isotopes Same # of protons but differ is # of neutrons Radioactive Isotopes- elements w/extra neutrons….unstable and it splits releasing positrons (positively chgd e-’s) that attract electrons of neighboring atoms (tracers) and generate a gamma ray…shows changing [] and location. PET Scans

5. Energy Levels of Electrons Electrons are the only subatomic structure that are involved in chem rxns Potential enery = stored energy e- dist potential energy Orbitals p37 Fig 2.10

6. Electron Configurations

7. Chemical Bonds Covalent – sharing e-’s

8. Chemical Bonds Polar Covalent bonds – e-’s are not shared equally. 1 atom is more electronegative than the other.

9. Chemical Bonds Nonpolar covalent bonds - share e-’s equally -O 2, H 2, CH 4

10. Chemical Bonds Ionic – transfer electrons from +/- ions Cation = + chgd ionAnion = - chgd ion Form Salts

11. Chemical Bonds Hydrogen Bonds – wk bonds amongst electronegative atoms. (H 2 O and NH 3 )

12. Van der Waals Van der Waals – occur between atoms and molecules that are close to each other.

13. Shape/Function A molecules shape determines its function Orbitals determine shape

14. Chem Rxns Reactants Products Equilibrium when reactants and products have concentrations stabilized