Biology Ch. 2

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Biology Ch. 2
2010-09-06 21:40:12
Biology Terms

Biology Exam 1
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    Anything that takes up space and has mass. Matter is made up by elements
    Capacity to do work and cause change. TWO TYPES: Potential and Kinetic
    Substance that cannot be broken down to other substances by simple chemical means
  4. Compound
    2 or more different elements in a fixed ratio
  5. Trace Element
    • Living Organisms need elements in small amounts (trace elements)
    • Ex: Fe, Zn, l, Se, etc. <0.01%
  6. Atom
    Smallest unit of matter that still retains the property of that element
  7. Neutron
    Subatomic particles in an atom that is electrically neutral. Deduced by subtracting the mass number (superscript) by the atomic number (subscript).
  8. Proton
    Subatomic particle of an atom that is positively charged and is in the nucleus. Defined by the atomic number of an element, which is unique to each element. (126C, 136C, 146C are all carbon because they all have 6 protons, unique to Carbon)
  9. Electron
    Subatomic particle of an atom that is negatively charged and is kept in the orbital region of the atom by the positive charges of the proton.
  10. Atomic Number
    The number of protons in an element (unique), found as a subscript 2He
  11. Dalton
    Small unit of measurements to describe weight of subatomic particles such as protons and neutrons.
  12. Atomic Nucleus
    Protons and neutrons packed in a tight core and is positive by the protons.
  13. Mass Number
    Sum of protons and neutrons, found on the left side of the element in superscript. EX: 11C
  14. Atomic Weight
  15. Potential Energy
    Energy that matter has because of its location or structure (like water in a dam). Has more energy at top and less at the bottom.
  16. Isotope
    Atoms usually have the same number of protons and neutrons of a given element; however, isotopes have more neutrons of a given element that give it a greater mass. Ex. Carbon 12, Carbon 13, Carbon 14.
  17. Energy Level
    Electrons energy level is correlated with the average distance to the nucleus. First shell, closest to nucleus, electrons have the lowest energy level.
  18. Electron Shell
    Electron shell is where electrons reside, each with its characteristic average distance and energy level.
  19. Valence Electron
    Chemical Behavior is due to electrons in the outermost shell: valence electrons.
  20. Valence Shell
    The outermost shell of an atom. Atoms with similar numbers of electrons in Valence Shells exhibit same behavior.
  21. Orbital
    is where electrons spend 90% of their time.
  22. Chemical Bond
    is the attraction of Atoms, combine by sharing or transferring valence electrons.
  23. Covalent Bond
    Sharing of electrons (covalent/cover/warm). Ex Hydrogen with 1 valence electrons, share electrons with other hydrogens.
  24. Molecule
    2 or more of the SAME atoms when joined by COVALENT bonds.
  25. Structural Formula
    Notation that represents atoms and bond. EX. H-H (shows that it is shared)
  26. Molecular Formula
    H(sub2) shows that it has 2 Hydrogen molecules.
  27. Double Covalent Bond
    Bond by sharing 2 electrons (such as oxygen)
  28. Valence
    bonding capacity is the atom's valence. (2 fulfill atoms outermost valence shell)
  29. Nonpolar Covalent Bond
    Bond when atoms electronegativity are similar to each other. Ex. 2 Hydrogen bonds with the same electronegativity.
  30. Radioactive Isotope
    Stable vs. Unstable Isotopes: C12 and C13 are stable (don't have tendency to lose particles). C14 is unstable where nucleus spontaneous decays, giving off particles and energy.
  31. Electronegativity
    Is the particular attraction of atom's electrons of a covalent bond. Stronger the electronegativity, stronger it pulls other shared electrons.
  32. Polar Covalent Bond
    Bond when one atom is more electronegative than another, it is a polar covalent bond.
  33. Ion
    A charged atom/molecule
  34. Cation
    Positively charged ion.
  35. Anion
    Negatively charged ion.
  36. Ionic Bond
    Cations (positive charge) bond with Anions (negatively charged). Any two oppositely charged ions can form an ionic bond.
  37. Ionic Compound
    Compounds formed by ionic bonds such as NaCl (Sodium Chloride)
  38. Van Der Waals Interactions
    Nonpolar covalent bonds maybe be somewhat give a charge in some regions (electrons are not evenly disbursed); hence, bonds are weak and only happens when atoms or molecules are really close to each other. Ex. gecko lizard's hands can climb up walls.
  39. Chemical Reaction
    Takes place when chemical bonds make or break to change the composition of matter.
  40. Reactant
    Starting material of a chemical reaction.
  41. Product
    The end result of a chemical reaction. Reactants form the end results (product)
  42. Chemical Equilibrium
    reactions create a dynamic equilibrium that has no net affect and has stabilized at a particular ratio.