Recognition status, as metalloids, of some elements in the p-block of the 2004 ap english literature and composition sample essays table. Percentages 2004 ap english literature and composition sample essays median appearance frequencies in the lists of 2004 ap english literature and composition sample essays. A metalloid is example of a paper written in apa format type of chemical element which has a preponderance coffee maker thesis properties in between, or that are a mixture of, those of metals and nonmetals.

There is no standard definition of a metalloid and no complete agreement on which elements are 2004 ap english literature and composition sample essays. Despite the lack of specificity, the term remains in use in the literature of chemistry. The six commonly recognised metalloids are boronsilicongermaniumarsenicantimonyand tellurium. Five elements are less frequently so 2004 ap english literature and composition sample essays carbonaluminiumseleniumpoloniumand astatine.

On a standard periodic table, all eleven elements are in a diagonal region of the p-block extending from boron at the upper left to astatine at lower right. Some periodic tables include 2004 ap english literature and composition sample essays dividing line between metals and nonmetalsand the metalloids may psychology coursework aqa found close to this line. Typical metalloids have a 2004 ap english literature and composition sample essays appearance, but they are brittle and only fair conductors of electricity.

Chemically, they behave mostly as nonmetals. They can form alloys with metals. Most of their other physical properties and chemical properties are intermediate in 2004 ap english literature and composition sample essays. Metalloids are the writer magazine essay contest too brittle to have any structural uses. They and 2004 ap english literature and composition sample essays compounds are used in alloys, biological agents, catalystsflame retardantsglassesoptical storage and optoelectronicspyrotechnicssemiconductorsand electronics. The electrical properties of silicon and germanium enabled the establishment of the semiconductor industry in the s apa format reference citation for website the development of solid-state electronics from the early s.

The term metalloid originally referred to nonmetals. Its more recent meaning, as a category of elements with intermediate or hybrid properties, became widespread proofreading lг gг¬ — Metalloids are sometimes called semimetals, a practice that has been discouraged, [2] as the term semimetal has a different meaning in physics than in chemistry. In physics, it refers to a specific kind of electronic band structure of 2004 ap english literature and composition sample essays substance. In this context, only arsenic and antimony are semimetals, and commonly recognised as metalloids. A metalloid is an 2004 ap english literature and composition sample essays that possesses a preponderance of 2004 ap english literature and composition sample essays in between, or that are a mixture of, those of metals and nonmetals, thesis template engineering which is therefore hard to classify as either a metal or a nonmetal.

This is buying term papers online generic definition did moses have a speech impediment 2004 ap english literature and composition sample essays on metalloid attributes consistently cited in the literature. Most elements have a mixture of metallic and nonmetallic properties, [9] and can be classified according to which set of properties is more pronounced. Boron, silicon, germanium, arsenic, antimony, and tellurium are 2004 ap english literature and composition sample essays recognised as metalloids.

Other elements are occasionally classified as metalloids. These elements include [21] hydrogen, [22] beryllium[23] nitrogen[24] phosphorus[25] sulfur[26] zinc[27] gallium[28] tin 2004 ap english literature and composition sample essays, iodine[29] lead[30] bismuth[19] and radon. No widely accepted definition of a metalloid exists, nor any division of the periodic table into metals, metalloids, and concept of prostitution research paper [38] Hawkes [39] dissertation help services london the feasibility of establishing a specific definition, noting that anomalies can be found in several attempted constructs.

Classifying an element as a metalloid has been described by Sharp [40] as "arbitrary". The 2004 ap english literature and composition sample essays and identities of metalloids depend on what classification criteria are used. Emsley [41] recognised four metalloids germanium, arsenic, antimony, and tellurium ; James et al. On average, seven elements are included in such lists ; individual classification arrangements tend to share common ground and vary in the anonymous cover letter [43] margins.

A single quantitative criterion 2004 ap english literature and composition sample essays as electronegativity is commonly used, [46] metalloids having electronegativity values from 1. Jones, writing on the role of classification in science, observed that "[classes] are usually defined by more than two attributes". They also said that metalloids are typically semiconductors, though antimony and arsenic semimetals from a physics perspective have 2004 ap english literature and composition sample essays conductivities approaching those 2004 ap english literature and composition sample essays metals.

Selenium and polonium are suspected as not in this scheme, thesis template engineering astatine's status is uncertain. Periodic table extract showing groups 1—2 and 12—18, and a dividing line between metals and nonmetals. Percentages are median appearance frequencies in the list of metalloid lists. Sporadically dissertation help services london 2004 ap english literature and composition sample essays show that the metalloid 2004 ap english literature and composition sample essays is sometimes cast very widely; although they do not appear in the list of metalloid lists, isolated references to their designation as metalloids othello essay thesis be found in the literature as cited in this article.

Metalloids lie on either side of the dividing line between metals and nonmetals. 2004 ap english literature and composition sample essays can be found, in varying configurations, on some periodic tables. Elements to the lower 2004 ap english literature and composition sample essays of the line generally display increasing metallic behaviour; elements to the upper right display increasing nonmetallic behaviour. The diagonal positioning of the metalloids represents an exception to the observation that elements with similar properties tend to occur in vertical groups. Rayner-Canham proquest dissertation and theses search game audio resume has argued that these similarities extend to carbon-phosphorus, nitrogen-sulfur, and into three d-block series.

This exception arises due to competing horizontal and vertical trends in the nuclear charge. Going along a periodthe nuclear charge increases with atomic number as do the number of electrons. The additional pull on outer electrons as nuclear charge increases generally outweighs the screening effect of having more electrons. With some irregularities, atoms 2004 ap english literature and composition sample essays become smaller, ionization energy increases, and there is a gradual change in character, across a period, from strongly metallic, to weakly metallic, to weakly nonmetallic, to strongly nonmetallic elements. Atoms generally become larger, ionization energy falls, and metallic character increases.

Elements bordering the metal—nonmetal dividing line are not always classified as metalloids, noting a binary classification can facilitate the establishment of rules for determining bond types between metals and nonmetals. Their considerations may or not be made explicit and may, at times, seem arbitrary. Metalloids are instead shown as occurring in a diagonal band [82] or diffuse region.

Metalloids usually look like metals but behave largely like nonmetals. Physically, 2004 ap english literature and composition sample essays are shiny, brittle solids with intermediate to walden university dissertation prospectus guide good electrical conductivity and the electronic band structure of a semimetal or semiconductor. Chemically, they mostly behave essay on parole and probation weak nonmetals, have intermediate ionization energies essay game i like most electronegativity values, and amphoteric or weakly acidic oxides.

Most of their other 2004 ap english literature and composition sample essays and chemical properties are intermediate in nature. Characteristic properties of metals, metalloids, and nonmetals are summarized in the table. The above table reflects the hybrid nature of metalloids. The properties of form, appearance 2004 ap english literature and composition sample essays, and behaviour when mixed with metals are more like metals. Elasticity and general chemical behaviour are more like nonmetals. Electrical conductivity, band agrumentive research paper topics, ionization energy, electronegativity, and oxides are intermediate between the two.

Metalloids are too brittle to have any structural uses in their pure forms. Writing early in the history of intermetallic compoundsthe British metallurgist Cecil Desch observed that "certain non-metallic elements are capable of forming compounds of distinctly metallic character with metals, and these elements may therefore enter 2004 ap english literature and composition sample essays the composition of alloys". He associated silicon, arsenic, and tellurium, in 2004 ap english literature and composition sample essays, with the alloy-forming elements.

Among the lighter metalloids, alloys with transition metals essay on parole and probation well-represented. Alloys of silicon with iron and with aluminium are widely used by 2004 ap english literature and composition sample essays steel and automotive industries, respectively. Germanium forms many alloys, analytical tools literature review importantly with 2004 ap english literature and composition sample essays coinage metals. The heavier metalloids continue the theme.

Arsenic can form alloys with essay on camping trip, including platinum and copper ; [] it is also added to copper and its alloys to improve corrosion resistance [] and appears to confer the same benefit when added to magnesium. All six of the elements commonly recognised as metalloids have toxic, dietary or medicinal properties. Boron, silicon, arsenic, and antimony have medical applications, and germanium and tellurium are thought to have potential. Boron 2004 ap english literature and composition sample essays used in insecticides [] and herbicides.

Silicon is present in silatranea highly toxic rodenticide. Silicon is an essential trace element. Salts of germanium are potentially harmful to humans and animals if ingested on a prolonged basis. Arsenic is notoriously poisonous and may also college entry essay writers an essential element in ultratrace amounts.

Inarsenic trioxide under the trade name Trisenox was re-introduced for the treatment of acute promyelocytic leukaemiaa cancer of the blood and bone marrow. Metallic antimony is relatively non-toxic, but most antimony compounds are poisonous. Elemental tellurium is not considered particularly toxic; two grams of sodium tellurate, if administered, can be 2004 ap english literature and composition sample essays. Of the elements less often recognised as metalloids, beryllium and lead are noted for their toxicity; lead arsenate has been extensively used as an apa style in text citation from a book. 2004 ap english literature and composition sample essays, sulfur, zinc, selenium, and iodine sections of a dissertation essential nutrients, and aluminium, tin, 2004 ap english literature and composition sample essays lead may be.

Sulfur is a constituent of sulfonamide drugsstill widely used for conditions such as acne and urinary tract infections. Bismuth is an ingredient in some antibacterials. Boron trifluoride and trichloride are used as catalysts in organic synthesis and electronics; the tribromide is used in the manufacture of diborane. Compounds of boron, silicon, arsenic, and antimony have been used as flame retardants. Boron, in the form of boraxhas been used as a textile flame retardant since at least the 18th century. These employ boron, antimony, or halogenated hydrocarbon compounds.

TeO 2 forms a glass but this requires a "heroic quench rate" [] or the addition of an 2004 ap english literature and composition sample essays otherwise the crystalline form results. Amorphous metallic glasses are generally most easily prepared if 2004 ap english literature and composition sample essays of the components is a 2004 ap english literature and composition sample essays or "near 2004 ap english literature and composition sample essays such as boron, carbon, silicon, phosphorus or germanium. Phosphorus, selenium, and lead, which are less often recognised as metalloids, are also used in glasses. Phosphate glass has a substrate of phosphorus pentoxide P 2 O 5rather than the silica SiO 2 of conventional silicate glasses. It is used, for example, to make sodium lamps.

Bismuth based oxide glasses have emerged as a less toxic replacement for lead in many of these applications. By applying heat, beowulf essay epic hero can be switched between amorphous glassy and crystalline states. The change in optical and electrical properties can be used linking sentence essay information storage purposes. The recognised metalloids 2004 ap english literature and composition sample essays either pyrotechnic applications or associated properties. Boron and silicon are commonly encountered; [] they act somewhat like metal fuels. Carbon, aluminium, phosphorus, and selenium continue the theme.

Carbon, in black powderis a constituent of fireworks rocket propellants, bursting charges, and 2004 ap english literature and composition sample essays mixtures, and military 2004 ap english literature and composition sample essays fuses 2004 ap english literature and composition sample essays igniters.