Biology 196 Chapter 2 Class 1.1

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Biology 196 Chapter 2 Class 1.1
2012-06-04 18:51:40

Summer course 06/04/12
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  1. Atom
    Smallest unit of matter
  2. Nucleus
    Dense, positive charge containing protons and neutrons. Surrounded by electrons.
  3. Electrons
    • Negative charge
    • Negligible mass 0.005 Daltons
  4. Protons
    • Positive charge
    • 1.7 x 10^-24 grams (1 Dalton)
  5. Neutrons
    • No charge
    • 1 Dalton
  6. Element
    Pure substance that contains only one kind of atom
  7. Atomic Number
    Number of protons
  8. Atomic Mass
    Total number of protons and neutrons
  9. Atomic Weight
    Average of mass numbers of isotopes
  10. Isotopes
    Atom of an element with the same number of protons, but different numbers of neutrons
  11. Potential Energy
    Stored energy
  12. Electron Configuration
    Distribution of electrons
  13. Valence Electrons/ Valence Shell
    Outermost electron shells, determines how the atom combines with other atoms
  14. Electron Shells
    Energy levels around the nucleus, determine the reactivity of atoms
  15. S Orbitals
    Spherical, only orbital in first shell
  16. P Orbitals
    Dumbbell shape, 3 types (px, py, pz)
  17. Molecules
    2 or more atoms held together by covalent bonds
  18. Salts
    Ion bonds in stable solid compounds (Ionic compounds)
  19. Ions
    Electrically charged particles that form when atoms gain or lose one or more electrons
  20. Non-polar Covalent Bonds
    Electrons shared equally
  21. Polar Covalent Bonds
    Electrons shared unequally
  22. Electronegativity
    Nucleus attracts extra electrons (attractive force)
  23. Ionic Bonds
    Atom strips electrons from another atom
  24. Cations
    Positive charged ion
  25. Anion
    Negative charged ion
  26. Hydrogen Bonds
    • Weak bond
    • Weak interaction between H and O; H and N
  27. Van der Waals Interaction
    • When the atoms of two non-polar molecules are in close proximity
    • Weak interaction between electrons of one atom with nucleus of another atom
  28. Cohesion
    Capacity of water molecules to resist coming apart from one another when placed under tension (how well water sticks to water)
  29. Surface Tension
    Force to stretch/break liquid surface
  30. Specific Heat
    Amount of heat energy required to raise the temperature of 1 gram of that substance by 1*C
  31. Kilocalorie
    Unit of energy: 1 kg (l) of water 1*C, = food calorie
  32. pH
    • Measure of the acidity of a solution
    • pH 7= neutral
    • pH <7= basic
    • pH >7= acidic
  33. Acid
    Substance that increases the H+ concentration of a solution= H+ donor
  34. H+ Donor
    Acid, releases H+
  35. Base
    Substance that decreases the H+ concentrations of a solution= H+ acceptor
  36. H+ Acceptor
    Base, accepts H+
  37. Buffer
    • Substances that help biological fluids resist changes in pH
    • Usually weak acid/base combinations
    • Do not fully dissociate
  38. Compounds
    Substance made up of molecules with two or more elements bonded together
  39. Matter
    Neither created nor destroyed