What is the rarest chemical substance in the universe?

Most people may have kept from the Periodic Table of Elements only the bare minimum necessary to pass through some hairy tests during high school. But there are some curiosities that make it worth a quick revisit. For example, what is the rarest element found there? Answer: the status (At).

How rare? Much. In fact, there are currently only 31 grams of the substance on earth. In fact, their inclusion among the other chemical elements was effected at first only for a theoretical necessity - that is, there should be an element with 85 protons in its nucleus.

However, after some time, scientists were able to prove the substance by obtaining it in the laboratory. But the experience is of considerable difficulty. That's because the statate is so radioactive that it vaporizes itself when assembled in an appreciable amount! This is probably why, to this day, there is no practical application for the element - which is only for theoretical studies, and usually through its isotopes.