Of all the naturally occuring chemical elements, which of them has the fewest (if any) practical uses for mankind? Obivously thier presence in beneficial compounds counts as a useful purpose - but in and of itself, what’s the greatest waste of space on the periodic table?
Feel free to move to GD if better suited to that forum.
mm
I would imagine it’s going to be one of those unstable isotopes with a half life of some tiny fraction of a second, rendering it pretty difficult to use commercially, even if it did have interesting chemical properties.
So my vote goes to Astatine[sup]213[/sup]
How could something with a half life that short be a natrurally occuring element?
Astatine only occurs in miniscule quantities; the usual estimitate is that the earth’s crust has somewhere on the order of thirty grams or so of it altogether at any given time (francium only exists naturally in similar quantities.) Obviously neither of them is primordial in origin; they’re steps in the decay of heavier, longer-lived radioactive elements, though off the top of my head I’m not sure what the origin of either of them is. Most radioactive elements naturally present on earth are the result of the slow decay of uranium 238 and thorium 232. For instance, the longest-lived isotope of radium lasts about 1600 years, which works out to roughly 2.8 million half-lives since the formation of the earth. Clearly not much is left from then, but significant quantities can be found because it’s a breakdown product of U-238.
:smack: Of course.
Thanks.
I have read that Thulium is the least useful naturally occuring element.
Scandium (21) seems to exist only to take up space in the periodic table.
Most of the radioactives can be simply tacked on to the end of the periodic table. The true waste of space is technetium. It’s smack in the middle of the stable transition metals, yet here it is with no stable isotopes.
Wikipedia (yes, I know) describes Scandium as being used commercially in vapour lamps and aluminium alloys
Isn’t that supposed to be a wicked good poison?
I do recall one or two police shows where someone (always a woman, for some reason) was offing folks by spiking their drinks with thallium, and it wasn’t found until they specifically looked for it. In some cases, the killer had already buried a prior husband years before with the same technique and it wasn’t discovered until the body was exhumed and the hair tested for the metal.
It is defnitely used to make aluminum alloys. Smith & Wesson uses it in their revolvers to reduce weight, for instance.
Tholian Web -Likely made of a thulium thalium alloy, or possibly dithulium. 
Thulium show up in some high temperature superconductors, and also as a dopant in semiconductors.
Wow. Must be truly useless – I’ve never heard of it! (of course, that’s not necessarily the gold standard of what’s useful).
Depends on what you’re looking for in a poison, I guess, but I wouldn’t consider any of the heavy metals “good” poisons. The problem is that once a heavy metal, always a heavy metal. If you poison someone with an organic poison like cyanide, bury the body, and wait a few years, the cyanide will all decay into other innocuous compounds. Poison them with a heavy metal, though, and the forensics guys will still be able to detect it (if they look for it) in the remains millenia later.
You mean you’ve never heard this? Tom Lehrer's "The Elements". A Flash animation by Mike Stanfill, Private Hand (embedded flash)
How 'bout Actinium?
What a spiffy little tune. I’ll have to file it alongside the Alphabet Song in my mind so that I can easily call up the name of any of the elements on demand.
But techentium is an important radioactive tag in medical imaging. And so is thallium for that matter. Here.