Atomic Mass: 258ish amu
Melting Point: maybe around 827 °C
Boiling Point: they're not even guessing
Mendelevium is an extremely fakey element that you make by taking Einsteinium, itself a highly fakey element, and further provoking it by shooting helium nuclei at it and that sort of thing. It was first cooked up in 1955 by the University of California Golden Bears during an all-night physics binge -- really! -- and was formally named after Dmitri “Mr. Table of the Elements” Mendeleev a few years later.
There is very little Mendelevium around. It does not occur naturally, and it is impossible to manufacture with household equipment, and furthermore its most stable isotopes have a half-life of only one or two months. There are sixteen known isotopes of Mendelevium… but isn’t it interesting how the familiar patterns of words shape the way we think about the world? For there really aren’t ANY “known isotopes of Mendelevium,” if that phrasing implies that Mendelevium is a naturally occurring thing that people have gone out and learned about, so it could “known.” Let’s say that sixteen different isotopes of Mendelevium have been constructed through various chemical/physical procedures, with the two most recent having been brought into being in 1996.
There is some confusion about exactly how much of Mendelevium has been conjured into existence. The website of the Royal Society of Chemistry, which you’d expect to have the down-low, says that “only a few atoms have ever been created” and, further down the page, says that after the California experiments “further experiments yielded several thousand atoms of mendelevium, and today it is possible to produce millions of them.” MAKE UP YOUR MIND, ROYAL SOCIETY OF CHEMISTRY.
In conclusion, Mendelevium is a very ineresting element, and one well worth studying.
|The great chemist Dmitry Mendeleev, for whom Mendelevium was named, |
chillin' in his academic robes. Painted by Play-In Tournament artist Ilya Repin, 1885.