http://www.ck12.org Chapter 8. Ionic and Metallic Bonding
Ionic Bonds
As we saw in earlier chapters, the electrons in the outermost (valence) shell of an atom are largely responsible for the
ways in which that atom will interact with other elements. For example,Figure8.4 shows the electron configurations
of sodium (11 e−, 1 valence e−), neon (10 e−, 8 valence e−), and fluorine (9 e−, 7 valence e−).
FIGURE 8.4
This image shows the arrangement of
electrons in their ground states for
sodium, neon, and fluorine.Our model of ionic bonding and chemical reactivity states that sodium and fluorine have a strong driving force to
become isoelectronic with the nearest noble gas, neon. Because sodium needs to lose one electron and fluorine needs
to gain one for this to occur, one atom of sodium can give up its valence electron to a fluorine atom, resulting in
two ions with noble gas configurations matching that of neon (Figure8.5). The positive and negative ion are held
tightly together by electrostatic forces, which are strong forces between oppositely charged particles. When large
groups of sodium and fluorine atoms react in this way, the result is the ionic compound, sodium fluoride.
FIGURE 8.5
Electron arrangements for sodium fluoride.