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Rare-earth elements occur in nature in combination with phosphate ( monazite ), carbonate - fluoride ( bastnäsite ), and oxygen anions. In their oxides, most rare-earth elements only have a valence of 3 and form sesquioxides (cerium forms CeO2 ). Five different crystal structures are known, depending on the element and the temperature.
Lawrencium is a synthetic chemical element; it has symbol Lr (formerly Lw) and atomic number 103. It is named in honor of Ernest Lawrence, inventor of the cyclotron, a device that was used to discover many artificial radioactive elements. A radioactive metal, lawrencium is the eleventh transuranic element and the last member of the actinide series.
synthetic element. Atomic number color: black=solid. Group 9, by modern IUPAC numbering, [1] is a group (column) of chemical elements in the d-block of the periodic table. Members of Group 9 include cobalt (Co), rhodium (Rh), iridium (Ir) and meitnerium (Mt). [2] [page needed] These elements are among the rarest of the transition metals.
Element names are those accepted by IUPAC. Block indicates the periodic table block for each element: red = s-block, yellow = p-block, blue = d-block, green = f-block. Group and period refer to an element's position in the periodic table. Group numbers here show the currently accepted numbering; for older numberings, see Group (periodic table)
HALO →. The Power and Propulsion Element ( PPE ), previously known as the Asteroid Redirect Vehicle propulsion system, is a planned solar electric ion propulsion module being developed by Maxar Technologies for NASA. It is one of the major components of the Lunar Gateway. The PPE will allow access to the entire lunar surface and a wide range ...
The classical elements typically refer to earth, water, air, fire, and (later) aether which were proposed to explain the nature and complexity of all matter in terms of simpler substances. [1] [2] Ancient cultures in Greece, Angola, Tibet, India, and Mali had similar lists which sometimes referred, in local languages, to "air" as "wind" and the ...
23.6: Group 11: Copper, Silver, and Gold. The coinage metals—copper, silver, and gold—occur naturally (like the gold nugget shown here); consequently, these were probably the first metals used by ancient humans. For example, decorative gold artifacts dating from the late Stone Age are known, and some gold Egyptian coins are more than 5000 ...
