1. 60 40 20 0 FeCaKSPSiAlMgNaONCH Earth’s crust organisms Element Percent by Weight Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fig. 2.1 © Gunter Ziesler/Peter Arnold, Inc.

2. Fig. 2.2-1 c. Subatomic Particles = proton b. a. Particle ProtonNucleus+11 Atomic Mass Unit (AMU) Location Electric Charge Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

3. Fig. 2.2-2 c. Subatomic Particles = proton = neutron b. a. Particle Proton Neutron Nucleus +1 0 1 1 Atomic Mass Unit (AMU) Location Electric Charge Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

4. c. Subatomic Particles = proton = neutron = electron b. a. Particle Proton Neutron Electron Nucleus Electron shell +1 0 –1 1 1 0 Atomic Mass Unit (AMU) Location Electric Charge Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fig. 2.2

5. mass number atomic number atomic symbol Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Page 23

6. atomic number atomic symbolatomic mass Periods I 1 1.008 H 2 4.003 He IIIIIIVVVIVII 3 6.941 Li 4 9.012 Be 5 10.81 B 6 12.01 C 7 14.01 N 8 16.00 O 9 19.00 F 10 20.18 Ne 11 22.99 Na 12 24.31 Mg 13 26.98 Al 14 28.09 Si 15 30.97 P 16 32.07 S 17 35.45 Cl 18 39.95 Ar 19 39.10 K 20 40.08 Ca 31 69.72 Ga 32 72.59 Ge 33 74.92 As 34 78.96 Se 35 79.90 Br 36 83.60 Kr VIII Groups Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fig. 2.3

7. b. a. larynx thyroid gland trachea Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a: © Biomed Commun./Custom Medical Stock Photo; b(Right): © Hank Morgan/Rainbow; b(Left): © Mazzlota et al./Photo Researchers, Inc Fig. 2.4

8. electron electron shell nucleus hydrogen 1 1 H oxygen 16 8 O carbon 12 6 C nitrogen 14 7 N sulfur S 32 16 phosphorus P 31 15 H P S C O N Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fig. 2.6

9. Fig. 2.7-1 NaCl sodium atom (Na)chlorine atom (Cl) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

10. Fig. 2.7-2 Na Cl sodium atom (Na)chlorine atom (Cl) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

11. Fig. 2.7-3 + – NaCl Na Cl sodium ion (Na + ) chloride ion (Cl – ) sodium chloride (NaCl) sodium atom (Na)chlorine atom (Cl) a. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

12. O HH Oxygen is partially negative ( ) Hydrogens are partially positive ( ) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Page 27

13. a. Hydrogen gas b. Oxygen gas c. Methane Structural Formula Electron Model HCH HH H H OO C OO H H HH HH CH 4 O2O2 H2H2 Molecular Formula Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fig. 2.8

14. H HH Oxygen attracts the shared electrons and is partially negative. Hydrogens are partially positive. Ball-and-stick ModelElectron ModelSpace-filling Model H hydrogen bond H H HH a. Water (H 2 O) b. Hydrogen bonding between water molecules O O O O 104.5° Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fig. 2.9 ++ ++ –– –– ++ ++

15. freezing occursevaporation occurs a. Calories lost when 1 g of liquid water freezes and calories required when 1 g of liquid water evaporates. b. Bodies of organisms cool when their heat is used to evaporate water. Gas Liquid Solid 020408060100120 600 800 80 calories Temperature (°C) Calories of Heat Energy / g 540 calories 400 200 0 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Grant Taylor/Getty Images Fig. 2.10

16. H H HH HHH H HH H An ionic salt dissolves in water. HH Cl – Na + O O OO OO Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Page 30

17. N O O OO HH H H H A polar molecule dissolves in water. H HH HH H Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Page 30

18. Water evaporates, pulling the water column from the roots to the leaves. Water molecules cling together and adhere to sides of vessels in stems. Water enters a plant at root cells. H2OH2O H2OH2O Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fig. 2.11

19. ice layer Protists provide food for fish. River otters visit ice-covered ponds. Aquatic insects survive in air pockets. Freshwater fish take oxygen from water. 04100 1.0 0.9 Density (g/cm 3 ) Temperature (ºC) liquid water ice lattice Common frogs and pond turtles hibernate. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fig. 2.12

20. hydrogen ion hydroxide ion water Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Page 32

21. pH value 10 –1 10 –2 10 –3 10 –4 10 –5 10 –6 10 –7 10 –8 10 –9 10 –10 10 –11 10 –12 10 –13 10 –14 10 0 Examples hydrochloric acid acidic basic stomach acid, lemon juice vinegar, cola, beer tomatoes black coffee urine pure water seawater baking soda Great Salt Lake household ammonia household bleach sodium hydroxide 1 0 2 3 4 5 6 7 8 9 10 11 12 13 14 H + Ion Concentration Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fig. 2.13

22. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Page 32 [ H + ]p H 110 –6 6 110 –7 7 110 –8 8 (moles per liter) 0.000001 = 0.0000001 = 0.00000001 =

23. a.b. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a: © Lionel Delevingue/Phototake; b: © Mauritius, GMBH/Phototake Fig. 2A

24. Page 35 HH H H C Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

25. Page 35 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

26. 14 7 N N Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Page 36