All Elements Heavier Than Helium Are Metals?
Kirt's Cogitations™ #272

Astronomers consider all elements heavier than helium to be metals. That definition obviously does not jive with the standard chemical definition of a metal, but a concept called 'metallicity' argues that from a star (and therefore the universe) formation perspective, extremely high temperatures and pressures in first generation stars (like our sun) preclude the identification of distinct elements other than hydrogen and helium. Heavier elements, such as lithium - #3 on the periodic chart and actually considered a metal in chemistry - are overwhelmingly created after a massive enough hydrogen star collapses and begins fusing H and He into heavier elements.

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Posted April 7, 2016