https://pioneerworks.org/broadcast/picture-this-periodic-table
"The Periodic Table was conceived as a scheme for bringing order to the
elements. When there were deemed to be only four of these—the earth, air, fire,
and water of the Greek philosopher Empedocles (it was just one of the elemental
systems proposed in ancient times, but enjoyed the weighty advocacy of Plato
and Aristotle)—things seemed simple enough. But during the Renaissance, natural
philosophers were increasingly forced to accept that the metals then
known—copper, iron, lead, tin, mercury, silver and gold—were not as
interconvertible as the alchemists believed, but seemed to have an elemental
primacy about them, too. More and more of these became recognized—zinc,
bismuth, cobalt, and others—along with other new elements such as sulfur,
phosphorus, carbon, and, in the late eighteenth century, gaseous elements like
nitrogen, hydrogen and oxygen. When the French chemist Antoine Lavoisier (who
named those latter two) drew up a list of known elements for his seminal
textbook
Traité élémentaire de chemie in 1789, he counted 33—including light
and heat, which he called caloric.
The list didn’t seem to be arbitrary though. In the early nineteenth century,
several scientists noted that some elements seemed to come in families,
resembling one another in the kinds of reactions they engaged in and the
compounds they formed. Some claimed to see triads: the halogens chlorine,
bromine and iodine for example, or the reactive metals sodium, potassium (both
discovered by English chemist Humphry Davy in 1807) and lithium (identified in
1817). Was there a hidden pattern to the elements?"
Via Bill Daul.
Share and enjoy,
*** Xanni ***
--
mailto:xanni@xanadu.net Andrew Pam
http://xanadu.com.au/ Chief Scientist, Xanadu
https://glasswings.com.au/ Partner, Glass Wings
https://sericyb.com.au/ Manager, Serious Cybernetics
