1. BIOLOGIC CHEMISTRY Chapter 2 – Part 1 The Chemistry of Life CP Biology Paul VI Catholic High School

2. BIOLOGIC CHEMISTRY NATURE OF MATTER : ATOMS : “Basic unit of matter” An atom is the smallest portion of a substance that still retains the unique properties of that substance. PROTONS: Positive charge (1.009 DALTONS) NEUTRONS: No Charge (1.007 DALTONS) ELECTRONS: Negative charge (1/1840 DALTONS) 1 DALTON = 1.66054X10 -24 kilograms (1/12 the mass of Carbon)

3. BIOLOGIC CHEMISTRY NUCLEUS: CENTER OF ATOM CONTAINS PROTONS AND NEUTRONS ORBITALS: CONTAIN ELECTRONS In a neutral atom, the number of protons equals the number of electrons

4. BIOLOGIC CHEMISTRY ELECTRON CONFIGURATION: ENERGY LEVELS CONTAIN: 2, 8, 18, 32 electrons ENERGY SUBLEVELS: s level: 2 electrons p level: 6 electrons d level: 10 electrons f level: 14 electrons

5. Periodic chart (including Bohr models) BIOLOGIC CHEMISTRY

6. Periodic means repeating in a pattern The Periodic Table of Elements …is the arrangement of elements according to repeating changes in properties. The boxes for the elements are arranged in order of their atomic numbers. Vertical columns are groups or families. Horizontal rows are called periods. BIOLOGIC CHEMISTRY

7. ELEMENT: Atomic Number = protons Atomic Mass = protons + neutrons ISOTOPES: Vary in number neutrons Same Chemical Properties Some Radioactive

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9. RADIOACTIVE DECAY: α waves β waves γ waves CARBON DATING: “Half-Life” 5600 years

10. BIOLOGIC CHEMISTRY CHEMICAL COMPOUNDS: Substances formed by the combination of two or more different elements in a fixed ratio. They are “pure” substances. MOLECULE: Smallest unit of covalently bonded compound.

11. BIOLOGIC CHEMISTRY A chemical formula uses the symbols for the elements in the compound. Na + Cl → NaCl Some formulas include subscripts to show ratios of more than one atom. 2 H + 1 O → H 2 0

12. BIOLOGIC CHEMISTRY CHEMICAL FORMULA: Shorthand expression describing chemical composition SIMPLEST FORMULA CaN 2 O 6 (Empirical Formula) MOLECULAR FORMULACa(NO 3 ) 2 STRUCTURAL FORMULA

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15. CHEMICAL BONDS: Bond energy is the energy necessary to break a chemical bond. COVALENT BOND holds molecule together by sharing electrons IONIC BOND holds molecule together by transfer of electrons VAN DER WAALS FORCES temporary dipole attraction between molecules Results in higher boiling points HYDROGEN BONDS Attraction between molecules with partially positive and partially negative areas

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18. Hydrogen Bonding

19. BIOLOGIC CHEMISTRY Hydrogen bonds- partially positive charged “H”end of a molecule is attracted to partially negative charged end of another molecule

20. BIOLOGIC CHEMISTRY CHEMISTRY OF WATER: ATOMIC STRUCTURE: 10 Protons 10 Electrons Covalent Bond Polar Structure

21. BIOLOGIC CHEMISTRY PROPERTIES OF WATER: 1.COHESION: Attraction between molecules of the same substance. 2. ADHESION: Attraction between different substances. 3. HIGH SPECIFIC HEAT: 1Cal./gm/ o C 4. HIGH HEAT OF VAPORIZATION: (Heat energy required to change 1 gm. liquid water to gas.)

22. BIOLOGIC CHEMISTRY SOLUTION: Homogeneous (uniform) mixture of a liquid. solvent- dissolving agent solute- substance that is dissolved aqueous solution- solution with water as solvent MIXTURE: Substance composed of two or more elements or compounds that are together BUT are not chemically combined. SUSPENSION: Composed of nonpolar molecules in water. Water acts to exclude them.

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24. COLLOIDS: Heterogeneous mixtures containing particles intermediate in size between suspensions and solutions. TYNDALL EFFECT – light scattering effect in colloids

25. BIOLOGIC CHEMISTRY ACID / BASE / pH pH: (“ pouvoir hydrogene”) Calculated from the spontaneous dissociation of water Negative logarithm of the [H + ] Each change in a pH unit is a tenfold change in concentration

26. BIOLOGIC CHEMISTRY ACIDS: Any substance that dissociates in water to increase the H + concentration BASES: Any substance that dissociates to decrease the H + concentration.

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29. BUFFERS: Substance that acts as reservoir for H +. Carbonic Acid Buffer System

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