In 1809, the English chemist William Hyde Wollaston wrongly concluded that tantalum and columbium were identical. The English chemist Charles Hatchett reported a new element similar to tantalum in 1801, and named it columbium. Niobium has physical and chemical properties similar to those of the element tantalum, and the two are therefore difficult to distinguish. The name comes from Greek mythology: Niobe, daughter of Tantalus. It is a soft, grey, ductile transition metal, which is often found in the pyrochlore mineral, the main commercial source for niobium, and columbite. Niobium, or columbium, is a chemical element with the symbol Nb and atomic number 41. Yttrium has no known biological role, and exposure to yttrium compounds can cause lung disease in humans. Other uses include the production of electrodes, electrolytes, electronic filters, lasers and superconductors various medical applications and as traces in various materials to enhance their properties. The most important use of yttrium is in making phosphors, such as the red ones used in television set cathode ray tube (CRT) displays and in LEDs. Elemental yttrium was first isolated in 1828 by Friedrich Wöhler. Johan Gadolin discovered yttrium's oxide in Arrhenius' sample in 1789, and Anders Gustaf Ekeberg named the new oxide yttria. In 1787, Carl Axel Arrhenius found a new mineral near Ytterby in Sweden and named it ytterbite, after the village. Its only stable isotope, 89Y, is also its only naturally occurring isotope. Yttrium is almost always found combined with the lanthanides in rare earth minerals and is never found in nature as a free element. It is a silvery-metallic transition metal chemically similar to the lanthanides and it has often been classified as a " rare earth element". Yttrium is a chemical element with symbol Y and atomic number 39. (*) Exception to the Madelung rule s-block elements Rubidium This period is known to have a large number of exceptions to the Madelung rule.Įlements and their properties Chemical element Many later transition metals, such as rhodium, are very commonly used in jewelry as they are very shiny. Zirconium is one of the main components of zircon crystals, currently the oldest known minerals in the Earth's crust. Niobium has the largest known magnetic penetration depth of all the elements. This period contains technetium, one of the two elements until lead that has no stable isotopes (along with promethium), as well as molybdenum and iodine, two of the heaviest elements with a known biological role. As a rule, period 5 elements fill their 5s shells first, then their 4d, and 5p shells, in that order however, there are exceptions, such as rhodium. The fifth period contains 18 elements, beginning with rubidium and ending with xenon. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when chemical behaviour begins to repeat, meaning that elements with similar behaviour fall into the same vertical columns. A period 5 element is one of the chemical elements in the fifth row (or period) of the periodic table of the chemical elements.
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