Hi everyone! I guess you have
figured that this video is going to
be about such a metal as uranium.
However, let me make give a small
warning in order to calm you down. I
think now we have settled everything
and can move on to considering properties of the most dangerous metal on earth - uranium. Uranium belongs to the actinides series in the periodic table that is to radioactive elements and its atomic number is 92. Uranium is 40 times more abundant in earth’s crust than silver. It forms in abundance upon rapid neutron capture inside spinning supernovas. That is why uranium was discovered quite early, in Germany in 18-th century. Its discoverer, Martin Heinrich Klaproth, named it after a newly discovered planet of the solar system, after Uranus. In nature uranium is often found in such minerals as uraninite and autunite. This metal often has several oxidation states in those minerals. Thanks to the beautiful yellow colour of such minerals, glass blowers added them to glass. As a result minerals would give such glass a beautiful greenish colour. It’s a pity that back then craftsmen didn’t not about the toxicity of uranium compounds. Nevertheless, pure metallic uranium can be obtained from uranium ore via reduction by calcium which looks very ordinary. Since mostly uranium naturally occurs in the form of uranium-238 isotope with a half-life of about 4.468 billion years, in 99, 23% of cases to be precise. Depleted uranium is most frequently used for chemical researches, that is uranium-238, in order to reduce scientists’ exposure to its radiation. Also there are only two radioactive metals that occur naturally. Those are uranium and thorium. It’s so because of their extremely long half-lives. Pure uranium obtained from its ore looks quite dark as its surface oxidizes pretty fast because of the high chemical activeness of this metal. That is why it is often stored in argon and also all experiments with uranium are conducted in argon medium. Usually a piece of pure metallic uranium-238 is ripped to such small shreds on a lathe in a laboratory. It is noteworthy that these shreds in the test tube already emit beta and gamma radiation.
