Lanthanides Definition in Chemistry

Lanthanides Definition in Chemistry Below the main body of the periodic table are two rows of elements. These are the lanthanides and the actinides. If you look at the atomic numbers of the elements, youll notice they fit in the spaces below scandium and yttrium. The reason they arent (usually) listed there is because this would make the table too wide to print on paper. Each of these rows of elements has characteristic properties. Key Takeaways: What Are the Lanthanides? The lanthanides are the elements in the top of the two rows located below the main body of the periodic table.While there is disagreement over exactly which elements should be included, many chemists state the lanthanides are elements with atomic numbers 58 through 71.Atoms of these elements are characterized by having a partially filled 4f sublevel.These elements have several names, including the lanthanide series and the rare earth elements. The IUPAC preferred name is actually lanthanoids. Lanthanides Definition The lanthanides are generally considered to be elements with atomic numbers 58-71 (lanthanum to lutetium). The lanthanide series is the group of elements in which the 4f sublevel is being filled. All of these elements are metals (specifically, transition metals). They share several common properties. However, there is some dispute over exactly where the lanthanides begin and end. Technically, either lanthanum or lutetium is a d-block element rather than f-block element. Yet, the two elements share characteristics with other elements in the group. Nomenclature The lanthanides are indicated by the chemical symbol Ln when discussing general lanthanide chemistry. The group of elements actually goes by any of several names: lanthanides, lanthanide series, rare earth metals, rare earth elements, common earth elements, inner transition metals, and lanthanoids. The IUPAC formally prefers the use of the term lanthanoids because the suffix -ide has a specific meaning in chemistry. However, the group acknowledges the term lanthanide predates this decision, so it is generally accepted. Lanthanide Elements The lanthanides are: Lanthanum, atomic number 58Cerium, atomic number 58Praseodymium, atomic number 60Neodymium, atomic number 61Samarium, atomic number 62Europium, atomic number 63Gadolinium, atomic number 64Terbium, atomic number 65Dysprosium, atomic number 66Holmium, atomic number 67Erbium, atomic number 68Thulium, atomic number 69Ytterbium, atomic number 70Lutetium, atomic number 71 General Properties All of the lanthanides are shiny, silver-colored transition metals. Like other transition metals, they form colored solutions, however, lanthanide solutions tend to be pale in color. The lanthanides tend to be soft metals that can be cut with a knife. While the atoms can exhibit any of several oxidation states, the 3 state is most common. The metals are generally quite reactive and form an oxide coating upon exposure to air. Lanthanum, cerium, praseodymium, neodymium, and europium are so reactive they are stored in mineral oil. However, gadolinium and lutetium only slowly tarnish in air. Most lanthanides and their alloys quickly dissolve in acid, ignite in air around 150-200  °C, and react with halogens, sulfur, hydrogen, carbon, or nitrogen upon heating. Elements of the lanthanide series also display a phenomenon called lanthanide contraction. In lanthanide contraction, the 5s and 5p orbitals penetrate into the 4f subshell. Because the 4f subshell is not fully shielded from the effects of the positive nuclear charge, the atomic radius of the lanthanide atoms successively decreasing moving across the periodic table from left to right. (Note: This is, in fact, the general trend for atomic radius moving across the periodic table.) Occurrence in Nature Lanthanide minerals tend to contain all elements within the series. However, the vary according to the abundance of each element. The mineral euxenite contains lanthanides in nearly equal proportions. Monazite contains mainly lighter lanthanides, while xenotime contains mostly heavier lanthanides. Sources Cotton, Simon (2006).  Lanthanide and Actinide Chemistry. John Wiley Sons Ltd.Gray, Theodore (2009). The Elements: A Visual Exploration of Every Known Atom in the Universe. New York: Black Dog Leventhal Publishers. p. 240. ISBN 978-1-57912-814-2.Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. pp. 1230–1242. ISBN 978-0-08-037941-8.Krishnamurthy, Nagaiyar and Gupta, Chiranjib Kumar (2004). Extractive Metallurgy of Rare Earths. CRC Press. ISBN 0-415-33340-7.Wells, A. F. (1984). Structural Inorganic Chemistry (5th ed.). Oxford Science Publication. ISBN 978-0-19-855370-0.

Mr. and Mrs. and More

Mr. and Mrs. and More Mr. and Mrs. and More Mr. and Mrs. and More By Mark Nichol This post details the permutations of abbreviations for courtesy titles. As mentioned in this post, mister developed as a variant of master. (Interestingly, the newer title came to pertain to married men, while master, once a title of respect for a social superior, was reserved for unmarried men and boys.) Originally, both master and mister were abbreviated Mr. before a person’s name as a courtesy title, but as master fell out of use, Mr. came to be applied solely as an abbreviation for mister. Mrs. was originally a generic abbreviation of mistress before a name, but it developed into a courtesy title specifically for a married or widowed woman, while Miss, with no abbreviation, was adopted as an honorific for unmarried women. Ms. began as a variant abbreviation of mistress as a courtesy title in the 1600s but fell out of favor. (At the turn of the twentieth century, it was proposed as a substitute form of address for a woman whose marital status is unknown, but the idea did not gain traction, nor did the abbreviation catch on fifty years later when a couple of business publications brought the issue up again. However, after feminist and journalist Gloria Steinem adopted the abbreviation as the title of a new magazine for women in 1972, its use quickly spread.) Because no native plural form of Mr. or Mrs. developed in English, the French abbreviations Messrs. (Messieurs) and Mmes. (Mesdames) were borrowed; Mses. developed in imitation, and the plural form of Miss, Misses, like the singular form, did not acquire an abbreviation. Because of the decline in use of such honorifics, the plural forms are rarely seen anymore. As a reference to a man who embodies a certain quality, Mr. appears in such references as â€Å"Mr. Right† (the ideal man for a woman to marry) or â€Å"Mr. Big† (a man of significant authority and/or status). Missus, a derivative of mistress based on a casual pronunciation of the latter word, and Miz, a spelling based on the pronunciation of Mrs. or Miss in the southern United States, should generally be used only in dialogue in historically or geographically appropriate fiction. However, â€Å"the Mrs.† or â€Å"the missus,† spelled as shown as humorous references to one’s wife, are appropriate in informal writing. Want to improve your English in five minutes a day? Get a subscription and start receiving our writing tips and exercises daily! Keep learning! Browse the Style category, check our popular posts, or choose a related post below:100 Mostly Small But Expressive Interjections"Confused With" and "Confused About"The Difference Between "Phonics" and "Phonetics"