Group of chemical elements - Americium. Was synthesized in 1944-45 by Glenn T. James, and Leon O. Morgan, at the Metallurgical Laboratory of the University of Chicago by irradiation of Plutonium with neutrons. Discovery it became clear that the heavy transuranium elements. Contains six 5f electrons, and it is similar to europium which contains six 4f electrons. That was the reason to name the element number 95 americium.

In 1970 researchers led by Albert Ghiorso at the Berkeley Laboratory of the University of California by bombardment of californium with nitrogen ions and named Hahnium. Also this element was named Nielsbohrium.

Was discovered in the debris from the thermonuclear explosion in the Pacific Ocean in November 1952. Furthermore, this debris contains extremely heavy uranium and plutonium nucleus, such as. Formation of such nucleus can only be performed if.

Element Niobium, Nb, Transition Metal. Main article History of Niobium. After Niobe, daughter of Tantalus in Greek mythology. Main article Occurrence of Niobium. The crustal abundance of Niobium. It occurs in the minerals columbite columbite-tantalite or coltan, pyrochlore and loparite.

Had been discovered in 1940 by Edwin M. Kennedy, and Arthur C. Wahl at the Berkeley Laboratory of the University of California by bombardment of uranium oxide U. With deuterons highly accelerated in the 60-inch Berkeley cyclotron. Later was found out that this reaction yields a short-lived Neptunium-238 isotope which, in his turn, produces Plutonium-238. Via bombardment of uranium with deuterons highly accelerated in the cyclotron.

Block elements, corresponding to the filling of the 4 f. Electron shell in lanthanoides and 5 f.

Element Tantalum, Ta, Transition Metal. The discovery of transition metal tantalum. Symbolizing oxide is insoluble in acid, and was unable, just as the mythological Tantalos. Ekeberg called the ores in which tantalum. Was discovered tantalite and yttrotantalite. Perhaps Ekeberg isolated impure tantalum. Deep layers and upper mantle are poor by tantalum.

Element Thorium, Th, Actinide or Actinoid. It was done by Lars Frederik Nilson in 1882. Is a member of actinide. Isotope is the most long-lived and is found in nature. Are known, the most important of which are thorite Th.

Element Zirconium, Zr, Transition Metal. Containing mineral hyacinth or a jargon from Sri Lanka, originally known as Ceylon has been known from deepest ages for its beautiful colors, from yellow-golden, brownish, to fumous-green. Hyacinth was considered to be a sort of topaz or ruby, with similar chemical compound, a gemstone now known as zircon. These minerals were not known to contain this element until Klaproth, in 1789, analyzed jargon. Was first prepared in 1914.

Group of chemical elements - Curium. In which the first letter C. Is the initial of Curie and m. Is the initial of Marie. Does not have stable isotopes. 15 isotopes with mass numbers from 237 to 251 are currently known. The most long-lived of them are.