Atomic number consistent with the modern practice of ordering the elements by proton number, "Z", but that number was not known or suspected at the time. A simple numbering based on periodic table position was never entirely satisfactory, however. Besides the case of iodine and tellurium, later several other pairs of elements (such as argon and potassium, cobalt and nickel) were known to have nearly identical or reversed atomic weights, thus requiring their placement in the periodic table to be determined by their chemical properties. However the gradual identification of more and more chemically similar lanthanide elements, whose atomic number was not
Period 5 element be colored by anodization are particular advantages. Molybdenum is a Group 6 chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin "Molybdaenum", from Ancient Greek , meaning "lead", itself proposed as a loanword from Anatolian Luvian and Lydian languages, since its ores were confused with lead ores. The free element, which is a silvery metal, has the sixth-highest melting point of any element. It readily forms hard, stable carbides, and for this reason it is often used in high-strength steel alloys. Molybdenum does not occur as a free metal on Earth, but rather in