Search results
Results From The WOW.Com Content Network
Osmium (from Ancient Greek ὀσμή (osmḗ) 'smell') is a chemical element; it has symbol Os and atomic number 76. It 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. Osmium is the densest naturally occurring element.
Astatine is a chemical element; it has symbol At and atomic number 85. It is the rarest naturally occurring element in the Earth's crust, occurring only as the decay product of various heavier elements.
World Book Encyclopedia, Exploring Earth. HyperPhysics, Georgia State University, Abundance of Elements in Earth's Crust. Eric Scerri, The Periodic Table, Its Story and Its Significance, Oxford University Press, 2007 "EarthRef.org Digital Archive (ERDA) -- Major Element Composition of the Core vs the Bulk Earth". earthref.org
The collection includes videos, each just a few minutes long, for all 118 known elements with a video for each element, as well as many additional supplemental chemistry videos. The 118 element videos and introduction videos were all shot unscripted in June and July 2008. [5] Since the initial videos were completed in 2008 the team has been ...
The abundance of the chemical elements is a measure of the occurrences of the chemical elements relative to all other elements in a given environment. Abundance is measured in one of three ways: by mass fraction (in commercial contexts often called weight fraction), by mole fraction (fraction of atoms by numerical count, or sometimes fraction of molecules in gases), or by volume fraction.
It is a rare-earth element and the eleventh member of the lanthanide series. It is a relatively soft, silvery, fairly corrosion-resistant and malleable metal. Like many other lanthanides, holmium is too reactive to be found in native form, as pure holmium slowly forms a yellowish oxide coating when exposed to air. When isolated, holmium is ...
Yttrium is almost always found in combination with lanthanide elements in rare-earth minerals and is never found in nature as a free element. 89 Y is the only stable isotope and the only isotope found in the Earth's crust. The most important present-day use of yttrium is as a component of phosphors, especially those used in LEDs.
Lanthanum is the strongest and hardest base among the rare earth elements, which is again expected from its being the largest of them. [34] Some lanthanum(II) compounds are also known, but they are much less stable. [17] Therefore, in officially naming compounds of lanthanum its oxidation number always is to be mentioned.