Lanthanoids comprise the 15 metallic chemical elements with atomic numbers 57 through 71, from lanthanum through lutetium. Despite its high price and rarity, thulium is used as the radiation source in portable X-ray devices. Zirconium is mainly used as a refractory and opacifier, although small amounts are used as an alloying agent for its strong resistance to corrosion. Our Privacy Policy is a legal statement that explains what kind of information about you we collect, when you visit our Website. The atomic radius of Tungsten atom is 162pm (covalent radius). The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal. Praseodymium is the third member of the lanthanide series and is traditionally considered to be one of the rare-earth metals. Holmium is a relatively soft and malleable silvery-white metal. Berkelium is a member of the actinide and transuranium element series. Oxygen is a colourless, odourless reactive gas, the chemical element of atomic number 8 and the life-supporting component of the air. While resistivity is a material property, resistance is the property of an object. It is the heaviest essential mineral nutrient. Consequently, the smallest atom is helium with a radius of 32 pm, while one of the largest is caesium at 225 pm. The chemical symbol for Radon is Rn. Osmium is the densest naturally occurring element, with a density of 22.59 g/cm3. For uranium atom, the Van der Waals radius is about 186 pm = 1.86 ×10−10m. Discoverer: Davy, Sir H. and Thénard, L.-J. and Gay-Lussac, L.-J. Conductors are made of high-conductivity materials such as metals, in particular copper and aluminium. Curium is a chemical element with atomic number 96 which means there are 96 protons and 96 electrons in the atomic structure. A low resistivity indicates a material that readily allows the flow of electric current. Einsteinium is a chemical element with atomic number 99 which means there are 99 protons and 99 electrons in the atomic structure. Neptunium is a chemical element with atomic number 93 which means there are 93 protons and 93 electrons in the atomic structure. It has an estimated density of 40.7 x 103 kg/m3. The chemical symbol for Technetium is Tc. The chemical symbol for Cadmium is Cd. Neptunium is the first transuranic element. The chemical symbol for Helium is He. What is Radius and Density of Atomic Nucleus - Definition. The terms low spin and high spin refer to the electronic configurations of particular geomtries of certain d-block metal ions. Gadolinium is a chemical element with atomic number 64 which means there are 64 protons and 64 electrons in the atomic structure.