Chem 31: Chapter 12

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Chem 31: Chapter 12
2011-10-02 17:54:21
Chemistry Midterm Chapter 12

Vocabulary terms from Chapter 12 for Chem 31L
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  1. Electromagnetic radiation
    Contains electrical and magnetic fields that simultaneously oscillate in perpendicular planes through space, allowing energy to propagate mediums
  2. Wavelength
    The distance between two consecutive crests or troughs of a wave
  3. Frequency
    Number of cycles per second that pass a given point in space
  4. Hertz
    Common unit for frequency
  5. Blackbody radiation
    Radiation that originates solely from an idealized object that absorbs all radiation
  6. Ultraviolet catastrophe
    A radiation profile with no maximum that goes to infinite intensity at very short wavelengths
  7. Photoelectric effect
    The phenomenon by which electrons are emitted from the surface of a metal when light strikes it
  8. Dual nature of light
    The phenomenon by which light exhibits properties of both waves and particles
  9. deBroglie's Equation
    Derived the relationship between a particle's wavelength and momentum
  10. Diffraction
    The scattering of light from a regular array of points or lines
  11. Continuous spectrum
    Contains all the wavelengths of visible light; not quantized (ex. white light)
  12. Line spectrum
    Only a few lines result, each corresponding to a discrete wavelength (ex. hydrogen emission spectrum)
  13. Bohr's quantum model
    The electron in a hydrogen atom moves around the nucleus only in certain "allowed" orbits
  14. Ground state
    Lowest possible energy state
  15. Wave/quantum mechanics
    Approach to describing atoms taken by deBroglie and Schrodinger, in which emphasis was given to the wave properties of the electron
  16. Wave function
    An electron's coordinates in (x,y,z) form
  17. Operator
    A set of mathematical instructions for describing wave function
  18. Orbital
    A specific wave function for an electron
  19. Heisenberg's Uncertainty Principle
    There is a fundamental limitation to just how precisely we can know both the position and momentum of a given particle at a given time.
  20. Probability distribution
    indicates the probability value of an electron at a given point in space
  21. Radial probability distribution
    Total probability of finding the electron in a hydrogen atom at a particular distance from the nucleus
  22. Principle quantum number
    Related to the size and energy of an orbital
  23. Angular momentum quantum number
    Relates to the shape of an orbital's subshell
  24. Magnetic quantum number
    Relates to the orbital's orientation in space
  25. Nodal surfaces
    Orbital areas with zero probability of having an electron
  26. Degenerate orbitals
    All orbitals with the same energy
  27. Electron spin quantum number
    fourth quantum number; can equal +1/2 or -1/2
  28. Pauli Exclusion Principle
    In a given atom, no two electrons can have the same set of four quantum numbers.
  29. Polyelectronic atoms
    Atoms with more than one electron
  30. Effective nuclear charge
    The apparent nuclear charge
  31. Self-consistent field (SCF) method
    A method in which a given electron is assumed to be moving in a potential energy field that is a result of the nucleus and the average "electron density" of all other electrons
  32. Triads
    Groups of three elements with similar properties, as discovered by Johann Dobereiner
  33. Octaves
    An arrangement by John Newlands that suggested properties of elements repeat in eights
  34. Aufbau Principle
    Protons are added one by one to the nucleus, to "build up" the elements; electrons are similarly added to these atomic orbitals.
  35. Hund's Rule
    The lowest-energy configuration for an atom is the one having the maximum number of unpaired electrons allowed by the Pauli principle in a particular set of degenerate orbitals.
  36. Valence electrons
    the electrons in the outermost principal quantum level of an atom
  37. Core electrons
    The inner electrons
  38. Lanthanide series
    A group of 14 elements corresponding to the 4f orbitals
  39. Actinide series
    A group of 14 elements corresponding to the 5f orbitals
  40. Rare earth elements
    The lanthanide and actinide series
  41. Main group/Representative elements
    Groups 1A-8A
  42. Penetration effect
    An outer electron can "penetrate" the core electrons and "feel" more of the nuclear charge
  43. Shielding
    The process by which inner electrons can protect outer electrons from partially feeling nuclear charge
  44. Ionization energy
    The energy required to remove an electron from a gaseous electron or ion
  45. Koopman's Theory
    The ionization energy of an atom is equal to the energy of the orbital from which it came
  46. Electron affinity
    The energy change associated with the addition of an electron to a gaseous atom
  47. Atomic radii
    Half the distance between atoms
  48. Metalloids/Semimetals
    Elements thta exhibit both metallic and nonmetallic properties