Because each halogen lacks one electron in its outer principal energy level,
these elements usually are acceptors of electrons (oxidizing agents). Fluorine is
the most active nonmetal in the periodic chart.
Some Important Halides and Their Uses
Hydrochloric
acid—common acid prepared in the laboratory by reacting sodium chloride
with concentrated sulfuric acid. It is used in many important
industrial processes.Silver
bromide and
silver iodide—halides used on photographic film. Light intensity is recorded by
developing as black metallic silver those portions of the film upon
which the light fell during exposure.Hydrofluoric
acid—acid used to etch glass by reacting with SiO 2 to release silicon
fluoride gas. Also used to frost lightbulbs.Fluorides
—used in drinking water and toothpaste to reduce tooth decay.NITROGEN FAMILY
The most common member of this family is nitrogen itself. It is a colorless,
odorless, tasteless, and rather inactive gas that makes up about four-fifths of the
air in our atmosphere. The inactivity of N 2 gas can be explained by the fact that
the two atoms of nitrogen are bonded by three covalent bonds (:N N:) that
require a great deal of energy to break. Since nitrogen must be “pushed” into
combining with other elements, many of its compounds tend to decompose
violently with a release of the energy that went into forming them.
Nature “fixes” nitrogen, or makes nitrogen combine, by means of a nitrogen-
fixing bacteria found in the roots of beans, peas, clover, and other leguminous