Unit I Ch2 Atoms Life - Atoms Molecules and Life Chapter 2...

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Unformatted text preview: Atoms, Molecules, and Life Chapter 2 Chapter 1 The Terminology of Matter Matter: occupies space & has mass Atom: smallest structural unit of matter = Atomic Theory 92 atoms = 92 Elements: can’t be normally broken down Chapter 2 Chapter 2 Three Subatomic Particles Proton: •Heavy, (+) charge, nucleus Neutron: •Heavy, neutral charge, nucleus Electron: •Light, (-) charge, orbitals p21 p21 Chapter 2 3 electron shell e- e- p+ p+ p+ n n e- nucleus Helium (He) Hydrogen (H) Atomic Models Chapter 2 Chapter 4 Elements Differ in # of Protons Atomic Number = # of protons; constant Diff. for each element Atomic Mass = # protons + # neutrons Change # of electrons: ions Change # of neutrons: isotopes Chapter 2 Chapter 5 Common Elements (by mass) in Human Body Common Elements (by mass) in Human Body Oxygen: 65% Carbon: 18.5% Hydrogen: 9.5% Nitrogen: 3.3% Calcium: 1.5% Phosphorus 1% 0.4% Potassium, 0.3% Sulfur, 0.2% Chlorine, 0.2% Sodium, 0.1% Magnesium, Trace Iron Atomic shells fill up: Atomic 2, 8, 8 2, Innermost ectron shell 2e2n 2p+ 8e8n 8p+ Oxyge +2p+ +2p +2n± +2e+7p+ +8n± +7e- Max Max 8e8e Max Max 2e2e Heliu m +4p+ +4n± +4e- 15e16n 15p+ +5p+ Phosphor+4n± +5e- Chapter 2 7 ƒ2-2 6e6n 6p+ Carb on 20e20n 20p+ Calcium Energy capture & release e- absorbs energy energy boosts e- to higher shell e­ drops back into lowershell, releasing energy energy light Used in Photosynthesis, Cellular Respiration, Light bulbs Chemical bonding based on # e­ in outer electron shell Chemical bonding based on # e­ in outer electron shell If outermost shell is full, atom is INERT Chemical bonds: attraction between atoms in a molecule; Reversible If atoms identical = element If atoms different = compound Covalent bonds are strongest Hydrophobic interactions: hydrophobic molecules avoiding H20 Hydrophobic interactions: hydrophobic molecules avoiding H (a) Electron transferred 11p+ 11n 17p+ 18n Sodium atom (neutral) (b) Chlorine atom (neutral) Attraction between opposite charges 11p+ 11n Sodium ion (+) Ionic Bonding in NaCl 17p+ 18n Chloride ion (–) Chapter 2 11 Na Na Na Na Na Na Na Na Na Na Na Na Na Na Na Na Ionic Bonding in NaCl Na - - - Na Cl Cl Cl Cl - - Na - - - Na - Cl Cl Cl Cl -Cl -Cl -Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Na Na Na Na - - Cl - Cl - Cl Cl Cl Cl Cl ƒ2-3c ƒ2-3c Chapter 2 12 Chapter 2 13 ƒ2-4a&b Water Is Covalent ƒ2-4c ƒ2-4c Chapter 2 14 Polar vs. Nonpolar Covalent Bonds Polar vs. Nonpolar Covalent Bonds Covalent e­ Surface Prefers Soluble bond shared other in is POLAR unequal Charged Charged molecules NONPOLA equal Uncharged Uncharged R molecules Types of Molecules H2O Hydrophilic Proteins, “H2O loving” salts, sugars, ions, CO2 Oil Hydrophobic Fats & oils “H2O fearing” Hydrophobic interactions between oil and H20 Hydrogen Bonds in H20 H+ – Hydrogen Bonds O ƒ2-5 ƒ2-5 Chapter 2 16 Water is excellent solvent: dissolves hydrophilic substances Water is excellent solvent: water hydrogen bond glucose hydroxyl group Chapter 2 Chapter 18 Properties of Water due to H bonds High Cohesion Surface Tension Adhesion Molecules stick together Produces: Resists penetration Polar H2O molecules stick to polar surfaces Chapter 2 Chapter 19 Cohesion among Water Molecules ƒ2-8 ƒ2-8 Chapter 2 20 Dissociation of H20 = neutral pH Acids release H+ in H2O pH Scale 1 unit = 10x change in H+ Buffer Buffer Minimizes changes in pH Bicarbonate Common blood buffer If blood too acidic HCO3­ + H+ H2CO3 (carbonic acid) If blood too basic H2CO3 + OH­ HCO3­ + H2O Chapter 2 Chapter 22 Water moderates effects of temperature changes Water moderates effects of temperature changes Temperature For H2O Specific Heat Reflects speed of molecules Entering heat energy breaks H+ bonds before speeding up individual molecules Energy to heat 1 gram by 1 deg C H2O Granite 1 calorie = HIGH 0.02 calorie Heat of vaporization high Liquid Water Liquid Water Heat of fusion high Solid Water Chapter 2 Chapter 25 The End Chapter 2 Chapter 26 ...
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