chem 177

  1. ionization energy
    • minimum energy required to remove an electron from gaseous atom/ion
    • first: Na(g)-> Na+(g) + e-
    • 2nd: Na+(g) -> Na2+(g) + e-
    • energy increases to remove from 1st,2nd, 3rd, etc. ionization energy levels
  2. ionization energy trends
    • as i.e. INCREASES, harder to remove electron
    • Generally INC. left to right, bottom to top (pull of electrons increases going bottom to up)
    • exceptions: high group 2 and 5 (having to add an extra electron to an already balanced electron orbital)
  3. electron affinity
    • energy that comes with adding an electron to a gaseous atom
    • measures attraction between e- and atom, so┬áthe more negative electron affinity = higher/easier attraction
    • NEGATIVE numbers (usually)
    • equation: Cl(g) + e- -> Cl-(g)
    • energy is released
  4. electron affinity trends
    • very high: halogens (G 7)
    • slightly high: 1,3,4,6
    • positive: some G 2, 5, ALL G 8 (to add an e-) to an already filled orbital decreases attraction
  5. electronegativity:
    • ability of atom (in a molecule) to attract electrons to itself
    • based off of electron affinity and ionization energy
    • INCREASES: left to right, bottom to top
  6. using electronegative values to calculate type of bond (non-polar, polar-covalent, ionic)
    • subtract one electronegative value from the other to get positive value
    • < 0.3 non polar
    • .3-2.0 polar covalent
    • >2 ionic
  7. resonance
    when molecule as alternate but equivalent resonance structures
Card Set
chem 177
ch. 7.1-5, 8 except sec.2, ch. 9