What is an element? Chemically, an element is a pure substance composed of
atoms that all have the same number of protons in the nucleus. That number
is the "atomic number" and specifies the element's position in the periodic
table. The atomic nucleus also contains neutrons. For each element, the
sum of the numbers of protons and neutrons is the approximate atomic weight.
Depending on the definition, 17 out of the 94 naturally occurring elements
are generally considered essential for the growth of plants.


--
Sincerely,
John A. Keslick, Jr.
Consulting Arborist
http://home.ccil.org/~treeman
and www.treedictionary.com
Beware of so-called tree experts who do not understand tree biology.
Storms, fires, floods, earthquakes, and volcanic eruptions keep reminding us
that we are not the boss.