List of Elements in the Lathanide Group

List of Elements in the Lathanide Group The lanthanides or lanthanoid series is a group of transition metals located on the periodic table in the first row (period) below the main body of the table. The lanthanides are commonly referred to as the rare earths, although many people group scandium and yttrium together with the rare earth elements. Its less confusing to call the lanthanides a subset of the rare earth metals. The Lanthanides Heres a list of the 15 elements that are lanthanides, which run from atomic number 57 (lanthanum or Ln) and 71 (lutetium or Lu): Lanthanum: atomic number 57 with symbol Ln Cerium: atomic number 58 with symbol Ce Praseodymium: atomic number 59Â  with symbol Pr Neodymium: atomic number 60 with symbol Nd Promethium: atomic number 61 with symbol Pm Samarium: atomic number 62 with symbol Sm Europium: atomic number 63 with symbol Eu Gadolinium: atomic number 64 with symbol Gd Terbium: atomic number 65 with symbol Tb Dysprosium: atomic number 66 with symbol Dy Holmium: atomic number 67 with symbol Ho Erbium: atomic number 68Â  with symbol Er Thulium: atomic number 69 with symbol Tm Ytterbium: atomic number 70 with symbol Yb Lutetium: atomic number 71 with symbol Lu Note sometimes that lanthanides are considered to be the elements following lanthanum on the periodic table, making it a group of 14 elements. Some references also exclude lutetium from the group because it has a single valence electron in the 5d shell. Properties of the Lanthanides Because the lanthanides are all transition metals, these elements share common characteristics associated with metals. In pure form, they are bright, metallic, and silvery in appearance. Because the elements can have a variety of oxidation states, they tend to form brightly colored complexes. The most common oxidation state for most of these elements is 3, although 2 and 4 are also generally stable. The metals are reactive, readily forming ionic compounds with other elements. Lanthanum, cerium, praseodymium, neodymium, and europium react with oxygen to form oxide coatings or tarnish after brief exposure to air. Because of their reactivity, pure lanthanides are stored in an inert atmosphere, such as argon, or are kept under mineral oil. Unlike other most other transition metals, the lanthanides tend to be soft, sometimes to the point where they can be cut with a knife. None of the elements occurs free in nature. Moving across the periodic table, the radius of the 3 ion of each successive element decreases. This phenomenon is called lanthanide contraction. Except for lutetium, all of the lanthanide elements are f-block elements, referring to the filling of the 4f electron shell. Although lutetium is a d-block element, its usually considered a lanthanide because it shares so many chemical properties with the other elements in the group. Although the elements are called rare earth metals, they arent particularly scarce in nature. However, its difficult and time-consuming to isolate them from each other from their ores, adding to their value. Lanthanides are valued for their use in electronics, particularly television and monitor displays. They are used in lighters, lasers, superconductors, to color glass, to make materials phosphorescent, and to control nuclear reactions. A Note About Notation The chemical symbol Ln may be used to refer to any lanthanide in general, not specifically the element lanthanum. This may be confusing, especially in situations where lanthanum itself isnt considered a member of the group!