Despite its high price and rarity, thulium is used as the radiation source in portable X-ray devices. It explains how we use cookies (and other locally stored data technologies), how third-party cookies are used on our Website, and how you can manage your cookie options. Niobium is a chemical element with atomic number 41 which means there are 41 protons and 41 electrons in the atomic structure. Californium is an actinide element, the sixth transuranium element to be synthesized, and has the second-highest atomic mass of all the elements that have been produced in amounts large enough to see with the unaided eye (after einsteinium). The atomic mass is carried by the atomic nucleus, which occupies only about 10-12 of the total volume of the atom or less, but it contains all the positive charge and at least 99.95% of the total mass of the atom. Francium is an alkali metal, that has one valence electron. Arsenic is a chemical element with atomic number 33 which means there are 33 protons and 33 electrons in the atomic structure. Although classified as a rare earth element, samarium is the 40th most abundant element in the Earth’s crust and is more common than such metals as tin. Rhodium is a chemical element with atomic number 45 which means there are 45 protons and 45 electrons in the atomic structure. One unified atomic mass unit is approximately the mass of one nucleon (either a single proton or neutron) and is numerically equivalent to 1 g/mol. Berzelius in 1824 in an impure state, and finally by the chemists D. Lely, Jr. and L. Hamburger in a pure Thulium is a chemical element with atomic number 69 which means there are 69 protons and 69 electrons in the atomic structure. Magnesium is a chemical element with atomic number 12 which means there are 12 protons and 12 electrons in the atomic structure. Nearly all technetium is produced synthetically, and only minute amounts are found in the Earth’s crust. Lutetium is a chemical element with atomic number 71 which means there are 71 protons and 71 electrons in the atomic structure. Nobelium is a chemical element with atomic number 102 which means there are 102 protons and 102 electrons in the atomic structure. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas, the first in the noble gas group in the periodic table. The densest material found on earth is the metal osmium, but its density pales by comparison to the densities of exotic astronomical objects such as white dwarf stars and neutron stars. This website does not use any proprietary data. Zirconium is a chemical element with symbol Zr and atomic number 40. Discoverer: Corson, Dale R. and Mackenzie, K. R. The actinide or actinoid series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium. The chemical symbol for Nitrogen is N. Nitrogen is a colourless, odourless unreactive gas that forms about 78% of the earth’s atmosphere. The standard SI unit is kilograms per cubic meter (kg/m3). Xenon is a colorless, dense, odorless noble gas found in the Earth’s atmosphere in trace amounts. Lawrencium is the final member of the actinide series. Osmium is a hard, brittle, bluish-white transition metal in the platinum group that is found as a trace element in alloys, mostly in platinum ores. The most stable known isotope, 269Hs, has a half-life of approximately 9.7 seconds. Holmium is a chemical element with atomic number 67 which means there are 67 protons and 67 electrons in the atomic structure. Density is defined as the mass per unit volume. Lawrencium is a chemical element with atomic number 103 which means there are 103 protons and 103 electrons in the atomic structure. Atomic mass (Da) Isotopic abundance (amount fraction) 90 Zr : 89.904 6988(8) 0.5145(4) 91 Zr : 90.905 6402(7) 0.1122(5) 92 Zr : 91.905 0353(7) 0.1715(3) 94 Zr : 93.906 313(1) 0.1738(4) 96 Zr : 95.908 2776(8) 0.0280(2) The atomic weight of Zr has been taken to be A r (Zr) = 91.22 since 1931, and this value was reconfirmed in 1969 when it was assessed as 91.22(1). It is the heaviest element that can be formed by neutron bombardment of lighter elements, and hence the last element that can be prepared in macroscopic quantities. The chemical properties of this silvery gray, crystalline transition metal are intermediate between rhenium and manganese. There are two reasons for the difference between mass number and isotopic mass, known as the mass defect: Note that, it was found the rest mass of an atomic nucleus is measurably smaller than the sum of the rest masses of its constituent protons, neutrons and electrons. © 2019 periodic-table.org / see also Tellurium is a brittle, mildly toxic, rare, silver-white metalloid. Thorium is moderately hard, malleable, and has a high melting point. » Boiling Point » Melting Point » Abundant » State at STP » Discovery Year About Zirconium . Astatine is the rarest naturally occurring element on the Earth’s crust. Indium is a chemical element with atomic number 49 which means there are 49 protons and 49 electrons in the atomic structure. Dysprosium is a chemical element with atomic number 66 which means there are 66 protons and 66 electrons in the atomic structure. These zirconium minerals generally have a hafnium content that varies from a few tenths of 1 percent to several percent. It is the eponym of the lanthanide series, a group of 15 similar elements between lanthanum and lutetium in the periodic table, of which lanthanum is the first and the prototype. Manganese is a metal with important industrial metal alloy uses, particularly in stainless steels. It is best dissolved in hydrofluoric acid, in which procedure the formation of anionic fluoro complexes is important in stabilizing the solution. Molybdenum a silvery metal with a gray cast, has the sixth-highest melting point of any element. The chemical symbol for Lanthanum is La. Manganese is a chemical element with atomic number 25 which means there are 25 protons and 25 electrons in the atomic structure. All of the alkali metals have a single valence electron in the outer electron shell, which is easily removed to create an ion with a positive charge – a cation, which combines with anions to form salts. The chemical symbol for Bismuth is Bi. Zirconium is produced by the same process as that used for titanium. Niobium is a soft, grey, ductile transition metal, often found in the minerals pyrochlore (the main commercial source for niobium) and columbite.