Period 5 element and because of its rarity, rhodium is usually alloyed with platinum or palladium and applied in high-temperature and corrosion-resistive coatings. White gold is often plated with a thin rhodium layer to improve its optical impression while sterling silver is often rhodium plated for tarnish resistance. Rhodium detectors are used in nuclear reactors to measure the neutron flux level. Palladium is a chemical element with the chemical symbol Pd and an atomic number of 46. It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named
Group 5 element the element dubnium. Vanadium is named for Vanadis, the Scandinavian goddess of love. Niobium is named for Niobe, a figure from Greek mythology. Tantalum is named for Tantalus, a figure from Greek mythology. Dubnium is named for Dubna, Russia, where it was discovered. There are 160 parts per million of vanadium in the earth's crust, making it the 19th most abundant element there. Soil contains on average 100 parts per million of vanadium, and seawater contains 1.5 parts per billion of vanadium. A typical human contains 285 parts per billion of vanadium. Over 60 vanadium ores are known, including vanadinite,