Look up: lanthanide

1. lanthanide
   Compare with actinide and inner transition metals. Elements 57-70 are called lanthanides. Electrons added during the Aufbau construction of lanthanide atoms go into the 4f subshell.
   Found on http://antoine.frostburg.edu/chem/senese
   
   
2. Lanthanide
   The lanthanides are a group of 15 elements.
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3. lanthanide
   Any of a series of 15 metallic elements (also known as rare earths) with atomic numbers 57 (lanthanum) to 71 (lutetium). One of its members, promethium, is radioactive. All occur in nature. Lanthanides are grouped because of their chemical similarities (most are trivalent, but some can be divalent o...
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4. Lanthanide
   The `lanthanide` or `lanthanoid` (IUPAC nomenclature) series comprises the fifteen metallic chemical elements with atomic numbers 57 through 71, from lanthanum through pages=240-->--><ref name="Holden2004">--> The fifteen lanthanides, along with chemically similar scandium and yttrium, ...
   Found on http://en.wikipedia.org/wiki/Lanthanide