2. Chapter 6.1 Atoms & their interactions

3. Units of Matter ….. l Atoms l Elements l Compounds & Molecules lClC, O, H, N, S lClCO 2, H 2 0, C 6 H 12 0 6

4. Common Molecules

5. Atoms of the same Element: l Same number of protons, electrons & neutrons l Same atomic structure

6. Atoms l Germanium Ge l Tunneling Microscope l Computer enhancement

7. Atomic Models

8. Rules for Bohr model: Atomic number = l # electrons = l # protons 1st shell = 2 paired electrons 2nd shell up to 8 3rd shell up to 8 l (-, outer shell) l (+, nucleus) Nucleus +2P,N ee He

9. Ions l Atoms that l Loose or l Gain l Electrons

10. Ionic Bonds =

11. Covalent BONDS l Share electrons l Stronger than ionic that l Donate or Gain electrons

12. pH l?l? pH l?l? pH scale l?l?affect us l?l?pH balanced shampoo

13. WATER: H 2 O l How many atoms? l ?Types of bonds? l ?Strong or Weak l ? Break

14. Water molecule…... l Covalent bonds l Polar l + charge at O end l - charge at H end l Pull apart ions

15. H 2 O-->H+ & OH- l H + = Hydrogen ion l in excess= acid l OH - = Hydroxide ion l in excess= base

16. How frequently do they break apart? l (10) - 7 concentration of H+ l.0000001 l 1 for every 10 million water molecules!

17. pH=measurement l -log of the {H+} l for water l = (10) - 7 l pH = 7 pH 2 pH4 pH8 pH10 pH12

18. ?H 2 0 a neutral pH l #hydrogen ions = #hydroxide ions. l H + = (10) - 7 l OH - = (10) - 7

19. ? Makes an acid l Increase the relative amount of H+ l adding a weak acid= l {H+}= 10 - 5 l ? pH l pH = 5

20. ?Base l {H+} lower than 10 - 7 l tips the balance of H+ to OH- l = more OH- than H+. l = base with pH 8 l =alkaline

21. ?strong or weak l The more acid the __________the pH number. l (lower) (1-5) l The more alkaline, the ________________ the pH (higher, above 7) (8-12)

22. Examples l Lemons l Vinegar l Aspirin l Battery acid sour

23. Bases l Ammonia l Lye l Sodium hydroxide l Baking soda slippery

26. ? living systems & pH challenges? l ? is low body pH l ?extreme pHs & cells l ?spills of strong acids or bases on your hand?

27. ?BUFFERS l ?buffered asprin l buffers take up excess H + or OH - ions l maintain constant pH l blood Homeostasis: CO 2 + H 2 O = H 2 CO 3