Isotopes (from the Greek
iso-, equal, and topos, place; in reference
to isotopes of an element having the same position in
the periodical table of elements) are forms of a given
chemical element that have different atomic masses.
The nuclei of isotopes of an element contain identical
numbers of protons, and so the isotopes have the same
atomic number. Each isotope has a different number of
neutrons and thus has a different atomic mass.
Most elements have both stable and
radioactive isotopes. Radioactive isotopes of an element
are commonly used as tracers in medical, biological,
and industrial studies to gain information about physical
and mechanical processes. In geology and archaeology,
radioactive isotopes are used to determine the age of
a sample. Hydrologists find
isotopes useful in their research in a variety of ways.
They are described in detail on this site.
additional general information on isotopes and hydrology,
see the January/February 2003 issue of Southwest
Hydrology focusing on "Tracking Groundwater
with Isotopes." The issue includes articles by
Brenda Ekwurzel, "Dating Groundwater With Isotopes,"
version or html version)
and by James Hogan, "Isotope Hydrology: Web and
Print Resources," (see pdf
version or html version).
Types of Isotopes:
- decay types
- types of radioactive
isotopes (by origin)