1. Fig. 2-4, p. 22

2. Hydrogen 62.0% Oxygen 24.0 Carbon 12.0 Nitrogen 1.2 Phosphorus 0.2
Calcium
Sodium 0.1
Potassium 0.1
Chlorine  0.1
Human
Earth
Hydrogen 66.0%
Oxygen 33.0
Carbon 0.1
Nitrogen 0.1
Phosphorus 0.1
Calcium 0.1
Sodium 0.3
Potassium 0.1
Chlorine
Seawater
Hydrogen 3.1%
Oxygen 60.0
Carbon 0.3
Nitrogen 0.1
Phosphorus 0.1
Calcium 2.6
Sodium 0.1
Potassium 0.8
Chlorine 0.1
Fig. 2-2, p. 21

3. Table 2-2, p. 32

4. nucleus
electron
Fig. 2-3, p. 22

5. electron sodium 11p+ , 11e- chlorine 17p+ , 17e- argon 18p+, 18e-
carbon
6p+ , 6e-
oxygen
8p+ , 8e-
neon
10p+, 10e-
hydrogen
1p+ , 1e-
helium
2p+ , 2e-
Fig. 2-6, p. 24

6. Sodium atom 11p+ 11e- Chlorine atom 17p+ 17e- no net charge no net
electron
loss
electron
gain
Chlorine atom
17p+
18e-
Sodium ion
11p+
10e-
net negative
charge
net positive
charge
Fig. 2-7, p. 25

7. A crystal of table salt is a cubic lattice of many sodium
ions and chloride ions. b
The mutual attraction of
opposite charges holds the
two kinds of ions together
closely in the lattice.
Sodium ion
Chloride ion
Fig. 2-8, p. 23

8. Two molecules interacting in one hydrogen (H) bond.
hydrogen bond
water molecule
ammonia molecule a
Two molecules interacting in one hydrogen (H) bond. b
Numerous H bonds ( white dots) hold the two coiled-up
strands of a DNA molecule together. Each H bond is weak,
but collectively these bonds stabilize DNA’s large structure.
Fig. 2-10, p. 27

9. Fig. 2-11, p. 28

10. O H H + + - slight negative charge on the oxygen atom
The positive and negative charges balance each other; overall, the molecule carries no charge. H H + +
slight positive charge on the hydrogen atoms
Fig. 2-11, p. 28

11. Fig. 2-13, p. 29

12. Fig. 2-17, p. 33

13. Table 2-2, p. 32

14. Fig. 2-14, p. 30 battery acid gastric fluid acid rain lemon juice cola
vinegar
orange juice
tomatoes, wine
bananas
beer
bread
black coffee
urine, tea, typical rain
corn
butter
milk
pure water
blood, tears
egg white
seawater
baking soda
phosphate detergents
Tums
toothpaste
hand soap
milk of magnesia
household ammonia
hair remover
bleach
oven cleaner
drain cleaner
Fig. 2-14, p. 30