Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 2 Image Slides

Fig. 2.2 Subatomic Particles = proton = neutron = electron b. a. Particle Proton Neutron Electron Nucleus Electron orbital +1 0 –1 1 1 ~0 Atomic MassLocation Electric Charge Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Fig. 2.3 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Groups I H He IIIIIIVVVIVII Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Ga Ge As Se Br Kr VIII Periods 11

Fig. 2.6a Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. electron electron orbital nucleus H C carbon 12 C 6 hydrogen 1 H 1 *The first electron orbital can hold 2 electrons, each orbital that follows can hold up to 8 electrons

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

Fig. 2.4 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. larynx thyroid gland trachea a: © Biomed Commun./Custom Medical Stock Photo; b(left): © Mazzlota et al./Photo Researchers, Inc; b(right): © Hank Morgan/Rainbow Isotopes: Same number of protons, different number of neutrons. Unstable isotopes give off radiation. Low level radioactive isotopes are helpful in medicine because they can be used as tracers and show doctors images of internal organs and tissues A PET Scan picks up radioactivity and makes an image

Fig. 2.7 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. sodium ion (Na + ) sodium chloride (NaCl) sodium atom (Na)chlorine atom (Cl) Na Cl + Na – Cl chloride ion (Cl + ) a.b. b: © The McGraw-Hill Companies, Inc./ Evelyn Jo Johnson photographer Ionic Bond: Sodium donates an electron and Chlorine accepts it. They now have 8 electrons in the outer shell between them

Fig. 2.8a Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. HH HH Molecular Formula Structural Formula Electron Model a. Hydrogen gas H2H2 Covalent Bond: Hydrogen only has 1 electron in its outer shell. 2 Hydrogen atoms can share their electrons and form hydrogen gas

Fig. 2.8b OO OO b. Oxygen gas O2O2 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Covalent Bond: Oxygen has 6 electrons in its outer shell. It can share 2 with another oxygen, forming oxygen gas.

Fig. 2.8c Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. c. Methane HH H H C HCH H H CH 4 Covalent Bonds can also form between 2 different atoms such as Hydrogen and Carbon. Hydrogen is sharing its electrons with Carbon to form Methane.

Non Polar Covalent BondPolar Covalent Bond * Charges shared are mostly equal * Charges shared are unequal Ex: H 2, O 2, CH 4 Ex. H 2 O

Fig. 2.9 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. ++ ++ –– ++ ++ –– H HH Hydrogens are partially positive. O Ball-and-stick ModelElectron ModelSpace-filling Model H O H H O O HH b. Hydrogen bonding between water molecules Oxygen attracts the shared electrons and is partially negative. hydrogen bond a. W ater (H 2 O) 104.5° Water is a polar covalent bond, because the electron sharing is unequal. Hydrogen bonding allows water molecules to stick to other water molecules. Hydrogen bonds are weak, yet strong enough to hold together other important biological molecules, such as DNA

Page 27 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. H H HH HHH H HH H ++ ++ ++ ++ HH O O OO OO –– –– Cl – Na + Since water is polar and has charges, it can easily dissolve other charged atoms. Water is a universal solvent.

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