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Lanthanum is a chemical element with the symbol La and the atomic number 57. It is a soft, ductile, silvery-white metal that tarnishes slowly when exposed to air. It is the eponym of the lanthanide series, a group of 15 similar elements between lanthanum and lutetium in the periodic table, of which
English: This pictorial periodic table is colorful, boring, and packed with information. In addition to the element's name, symbol, and atomic number, each element box has a drawing of one of the element's main human uses or natural occurrences. The table is color-coded to show the chemical groupings.
A mnemonic is a memory aid used to improve long-term memory and make the process of consolidation easier. Many chemistry aspects, rules, names of compounds, sequences of elements, their reactivity, etc., can be easily and efficiently memorized with the help of mnemonics.
Publishers Weekly said that the book was a "lively introduction to the chart that has been the bane of many a chemistry student", [5] and in a review in New Scientist, Vivienne Greig called The Periodic Table "an engrossing read and an ideal way to painlessly impart a great deal of science history to seen-it-all-before teenagers."
Like the periodic table, the list below organizes the elements by the number of protons in their atoms; it can also be organized by other properties, such as atomic weight, density, and electronegativity. For more detailed information about the origins of element names, see List of chemical element name etymologies.
Periodic table of the chemical elements showing the most or more commonly named sets of elements (in periodic tables), and a traditional dividing line between metals and nonmetals. The f-block actually fits between groups 2 and 3 ; it is usually shown at the foot of the table to save horizontal space.
Viewing the lanthanides from left to right in the periodic table, the seven 4f atomic orbitals become progressively more filled (see above and Periodic table § Electron configuration table). The electronic configuration of most neutral gas-phase lanthanide atoms is [Xe]6s 2 4f n , where n is 56 less than the atomic number Z .
A table listing the 17 rare-earth elements, their atomic number and symbol, the etymology of their names, and their main uses (see also Applications of lanthanides) is provided here. Some of the rare-earth elements are named after the scientists who discovered them, or elucidated their elemental properties, and some after the geographical ...