Environmental Engineering Reference
In-Depth Information
N Cs He
K Be Ar
S Sr C
Mg Cd Cu
Ca Pb Pb
Si Hg Ag
Fe Br Au
Micro
a
F
Fe
b
Cr Rn
Mn U
Cu
Zn
Mo
Co
Ni
P
Cl
a
Macro elements are present at relatively large levels and micro are relatively low levels.
b
Fe only counts if you consider meteorites.
column gives the elements sometimes found in elemental form in the environment.
All the natural elements are found someplace on the Earth. The elements mentioned
above, however, are common in all areas, while other elements are found in detectable
amounts only in restricted locations.
As stated above, these elements are found as ions combined with other ions in the
environment. In the case of inorganic compounds these are generally salts. The metals are
found as positive ions, or cations, and the nonmetals as negative ions, or anions, and in
some cases both can form negatively charged oxyanions when combined with oxygen.
(See below.) Carbon in organic compounds is not ionic, but forms compounds that do not
generally have full positive or negative charges.
*
*
Exceptions to this are organic acids, which can ionize to form anions, and amines, which act as
cations when they associate with protons.
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