Ionic Bonding Notes

Valence Electrons
Electrons in an atom's outer shell (valence shell).
Ion
Atoms that gives up or accepts electrons. These atoms now have an overall charge that is indicated with a positive or negative superscript number just behind the element or compound symbol. Examples:
  • Li+
  • Na+
  • Be2+
  • Cl
  • O2 –
  • (CO3)2 –     carbonate ion
  • (SO4)2 –     sulfate ion
  • (HCO3)     bicarbonate ion
  • (NH4)+     ammonium ion
  • (NO3)     nitrate ion
  • (OH)     hydroxide ion

Ionization Energy
Energy needed to remove an electron to form a positive ion. Atoms with few valence electrons tend to lose electrons rather than gain more. Examples: most metals.
Electron Affinity
The tendency for atoms to attract electrons. Atoms with many valence electrons tend to gain electrons rather than lose them since they often have high electron affinity and high ionization energy. Examples: most nonmetals.
e Donators
Atoms can transfer electrons to achieve a filled outer shell. Atoms such as sodium donate an electron and their ions have a net charge of +1. Na1+ has one less electron than it has protons. Its outer shell has 8 e- and is considered full.
e Acceptors
Atoms such as fluorine accept an electron and their ions have a net charge of -1.   F1- has one more electron than it has protons. Its outer shell has 8 e- and is full.
Ionic Bonds
Atoms that bond by transferring electrons. These compounds are held together by the strong attraction of their opposite charges that their ions have. Ionic compounds tend to :
  • high melting points.
  • well defined crystals.
  • not conduct electricity.
  • dissolve well in water.
Salts
Compounds that have a positive ion from a metal atom and a negative ion from a nonmetal. Example: NaCl (table salt)
NaCl ionic bond

  ionization bar graph ionization chart affinity bar graph affinity chart