1. 1 Unit 2: BIOMOLECULES, Part 1 INORGANIC CHEMISTRY Atomic structure and the periodic table Bonds – ionic, covalent (and hydrogen) Solubility and polarity, electrolytic properties Properties of water, hydrogen bonding Acids, bases and buffers

2. 2 Atomic structure Atomic number Atomic mass Number of electrons Electron energy levels # valence electrons  Number of protons  Number of protons + number of neutrons  (isotopes vary in # neutrons)  Equal to # of protons  Row on periodic table  Group # (1-8)  (active bonding electrons)

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4. 4 Bonds involve valence electrons Metals tend to transfer electrons Nonmetals tend to take electrons when bonding with metals Nonmetals tend to share electrons when bonding to other non-metals  Ions: charged atoms due to the gain or loss of electrons  Ionic bonds: cations and anions  Covalent bonds: shared electrons

5. 5 Covalent and Ionic bonds

6. 6 Ionic bonds Metals form cations when they lose valence electrons Nonmetals form anions when they gain valence electrons Generally are hydrophilic, dissolve in water, form electrolytes Ionic equations show the ions into which they separate

7. 7 Covalent bonds Shared electrons Non-metals to non-metals Do not form ions in solution May be polar or non-polar covalent Covalent bonds are stronger than ionic bonds CHNOPS compounds of living things (“organic”) are covalently bonded

8. 8 H 2 O is a polar molecule, covalently bonded but with an unequal distribution of shared electrons

9. 9 Water is the “versatile solvent” The hydrogen bonds between hydrogen and oxygen cause unique properties of water

10. 10 Polar solvents dissolve polar solutes Sugar dissolves in water Salt dissolves in water Only ionic compounds form electrolytes in water

11. 11 Nonpolar solutes do not dissolve in polar solvents (water) Salad oil Oil Gasoline Vegetable shortening butter

12. 12 Acids, Bases, Buffers Acids release H+ in solution Bases release OH- in solution Buffers resist changes in pH pHyrion paper

13. 13 pH scale

14. 14 Biological systems depend on buffers Narrow tolerances to changes in pH Acid rain alters pH of soils and aquatic ecosystems Limestone is used as a buffer in acidified lakes