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The Question
(Submitted March 26, 1998)
I was wondering, how many elements are known to exist to the present date?
(on the periodic table)
The Answer
The current total is now around 112. The ones up through atomic
number 92 (uranium) are naturally occurring, whereas the "transuranic"
elements are synthesized in experiments wherein heavy nuclei are made
to interact with each other.
There are a couple of informative articles in the magazine
Scientific American which describe this work, which was carried out
in the early days primarily in Berkeley, but now is done mainly in
Darmstadt, Germany. Here are the references:
-The Synthetic Elements, Seaborg & Bloom, April 1969
-Creating Superheavy Elements, Armbruster & Muenzenberg, May 1989
A website which contains the current periodic table of the elements is
http://www.shef.ac.uk/chemistry/web-elements/index-fr.html
By clicking on the symbol for each element, you can learn more about
that particular element.
J.K. Cannizzo
for Ask a High-Energy Astronomer
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