| 单词 | nonmetal |
| 例句 | A fourth, nonmetal piece,“Above Below Betwixt Between,” is an installation of flat, black rectangles made by applying paint to Belgian linen. Richard Serra’s Steel Behemoths Get Into Your Head 2016-05-12T04:00:00Z Conductors in the trash are slowed by magnetic damping while nonmetals in the trash move on, separating from the metals. College Physics for AP Courses 2015-08-12T00:00:00Z The charges of anions formed by the nonmetals may also be readily determined because these ions form when nonmetal atoms gain enough electrons to fill their valence shells. Chemistry 2019-02-14T00:00:00Z Figure 2.11 In the formation of an ionic compound, metals lose electrons and nonmetals gain electrons to achieve an octet. Biology for AP Courses 2022-06-09T00:00:00Z Another type, called a covalent or electron-sharing bond, commonly occurs between nonmetals. An Introduction to Geology 2017-01-01T00:00:00Z An undetectable firearm is defined as one constructed entirely of nonmetal substances, or with major components removed, so it is invisible to walk-through metal detectors. Delaware Democratic lawmakers take aim at ‘ghost guns’ 2021-03-12T05:00:00Z It also criminalizes “covert firearms” designed to not resemble a firearm, as well as “undetectable” firearms made of nonmetal substances so as not to set off metal detectors. Delaware lawmakers aim to outlaw “ghost guns” 2020-01-16T05:00:00Z When the electronegativity difference is very large, as is the case between metals and nonmetals, the bonding is characterized as ionic. Chemistry 2019-02-14T00:00:00Z Remember when the original purpose of nonmetal cleats was to avoid damaging greens? Gear & Gadgets: Best Cleats/Spikes - Golf Digest 2017-04-12T04:00:00Z The funds will be used to provide federally mandated training at all coal, metal and nonmetal mines. Feds dole out grants for mine safety courses 2016-07-07T04:00:00Z Main says 23 miners died in U.S. metal and nonmetal mines in fiscal 2015, down from 29 the previous fiscal year. US mine fatalities down over first 9 months of 2015 2015-10-27T04:00:00Z As a result, it is the leading polluter of cadmium, chromium, lead and nonmetal arsenic, according to data collected in 2011 by the Institute of Public and Environmental Affairs, a research group based in Beijing. Good Earth No More: Soil Pollution Plagues Chinese Countryside 2013-12-30T18:56:01Z For example, the pure metalloids form covalent crystals like the nonmetals, but like the metals, they generally do not form monatomic anions. Chemistry 2019-02-14T00:00:00Z For example, element 85 precipitates as a sulfide and is precipitated by zinc in sulfuric acid, both of which are reactions that are characteristic of a metal rather than a nonmetal such as iodine. A Tale of 7 Elements: Element 85 Astatine [Excerpt] 2013-07-05T14:15:00.623Z They are supposed to be able to find nonmetal weapons and other contraband—not just objects made of metal. The TSA's Dumb Air-Security Rules Are Not Based on Science 2012-06-26T12:15:06.343Z Five of those deaths were in metal and nonmetal mines and two occurred in coal mines. US mine fatalities down over first 9 months of 2015 2015-10-27T04:00:00Z His sense was humor was decent for a scientist – especially for an applied nonmetal materials engineer. A Noble Betrayal 2012-04-28T19:15:00.450Z Nonmetal structures contain covalent bonds, and many nonmetals consist of individual molecules. Chemistry 2019-02-14T00:00:00Z But the 20-year study from the National Cancer Institute took a closer look by tracking more than 12,000 workers in certain kinds of mines - facilities that mined for potash, lime and other nonmetals. Study links heavy diesel exhaust to lung cancer 2012-03-03T01:31:04Z Both the d- and f-block elements react with nonmetals to form binary compounds; heating is often required. Chemistry 2019-02-14T00:00:00Z Across a row in the periodic table, the acid strength of binary hydrogen compounds increases with increasing electronegativity of the nonmetal atom because the polarity of the H-A bond increases. Chemistry 2019-02-14T00:00:00Z A metalloid is an element that has properties that are between those of metals and nonmetals; these elements are typically semiconductors. Chemistry 2019-02-14T00:00:00Z Descriptions of the physical properties of three nonmetals that are characteristic of molecular solids follow. Chemistry 2019-02-14T00:00:00Z Their chemical behavior falls between that of metals and nonmetals. Chemistry 2019-02-14T00:00:00Z The nonmetals are elements located in the upper right portion of the periodic table. Chemistry 2019-02-14T00:00:00Z Under normal conditions, more than half of the nonmetals are gases, one is a liquid, and the rest include some of the softest and hardest of solids. Chemistry 2019-02-14T00:00:00Z The nonmetals exhibit a rich variety of chemical behaviors. Chemistry 2019-02-14T00:00:00Z P, I, Cl, and O would form anions because they are nonmetals. Chemistry 2019-02-14T00:00:00Z This section presents an overview of the properties and chemical behaviors of the nonmetals, as well as the chemistry of specific elements. Chemistry 2019-02-14T00:00:00Z Many of these nonmetals are important in biological systems. Chemistry 2019-02-14T00:00:00Z In many cases, trends in electronegativity enable us to predict the type of bonding and the physical states in compounds involving the nonmetals. Chemistry 2019-02-14T00:00:00Z The nonmetals have higher electronegativities than do metals, and compounds formed between metals and nonmetals are generally ionic in nature because of the large differences in electronegativity between them. Chemistry 2019-02-14T00:00:00Z Thus, the negative charge is better represented on the nonmetal, which has the greater tendency to attract electrons in the bond to itself. Chemistry 2019-02-14T00:00:00Z The metals form cations, the nonmetals form anions, and the resulting compounds are solids under normal conditions. Chemistry 2019-02-14T00:00:00Z On the other hand, compounds formed between two or more nonmetals have small differences in electronegativity between the atoms, and covalent bonding—sharing of electrons—results. Chemistry 2019-02-14T00:00:00Z The common oxidation states that the nonmetals exhibit in their ionic and covalent compounds are shown in Figure 18.19. Chemistry 2019-02-14T00:00:00Z The first member of each nonmetal group exhibits different behaviors, in many respects, from the other group members. Chemistry 2019-02-14T00:00:00Z As seen in this discussion, an important feature of the structural behavior of the nonmetals is that the elements usually occur with eight electrons in their valence shells. Chemistry 2019-02-14T00:00:00Z Nonmetals, other than the first member of each group, rarely form π bonds to nonmetals that are the first member of a group. Chemistry 2019-02-14T00:00:00Z The variety of oxidation states displayed by most of the nonmetals means that many of their chemical reactions involve changes in oxidation state through oxidation-reduction reactions. Chemistry 2019-02-14T00:00:00Z The oxidation state of the metal becomes positive as it undergoes oxidation and that of the nonmetal becomes negative as it undergoes reduction. Chemistry 2019-02-14T00:00:00Z With the exception of nitrogen and carbon, which are poor oxidizing agents, a more electronegative nonmetal oxidizes a less electronegative nonmetal or the anion of the nonmetal: Chemistry 2019-02-14T00:00:00Z The reactions of hydrogen with nonmetals generally produce acidic hydrogen compounds with hydrogen in the 1+ oxidation state. Chemistry 2019-02-14T00:00:00Z A nonmetal often oxidizes an element that lies to its left in the same period. Chemistry 2019-02-14T00:00:00Z The stronger a nonmetal is as an oxidizing agent, the more difficult it is to oxidize the anion formed by the nonmetal. Chemistry 2019-02-14T00:00:00Z With the exception of most of the noble gases, all nonmetals form compounds with oxygen, yielding covalent oxides. Chemistry 2019-02-14T00:00:00Z Those oxides such as NO2 and ClO2, in which the nonmetal does not exhibit one of its common oxidation states, also react with water. Chemistry 2019-02-14T00:00:00Z The reactions become more exothermic and vigorous as the electronegativity of the nonmetal increases. Chemistry 2019-02-14T00:00:00Z In these reactions, the nonmetal is both oxidized and reduced. Chemistry 2019-02-14T00:00:00Z The acid strength of the nonmetal hydrogen compounds increases from left to right across a period and down a group. Chemistry 2019-02-14T00:00:00Z The electrons in nonmetals are localized in covalent bonds, Chemistry 2019-02-14T00:00:00Z These elements are representative metals, metalloids, and nonmetals. Chemistry 2019-02-14T00:00:00Z For brevity, we will discuss only a few hydrogen compounds of the nonmetals here. Chemistry 2019-02-14T00:00:00Z The structures of these elements are similar in many ways to those of nonmetals, but the elements are electrical semiconductors. Chemistry 2019-02-14T00:00:00Z Molecular structures are common for most of the nonmetals, and several have multiple allotropes with varying physical properties. Chemistry 2019-02-14T00:00:00Z Although it has some chemical reactivity that is similar to that of the alkali metals, hydrogen has many of the same chemical properties of a nonmetal with a relatively low electronegativity. Chemistry 2019-02-14T00:00:00Z Bonds between two nonmetals are generally covalent; bonding between a metal and a nonmetal is often ionic. Chemistry 2019-02-14T00:00:00Z Most nonmetal oxides are acid anhydrides, meaning that they react with water to form acidic solutions. Chemistry 2019-02-14T00:00:00Z The metals of group 13 all react directly with nonmetals such as sulfur, phosphorus, and the halogens, forming binary compounds. Chemistry 2019-02-14T00:00:00Z This chapter explores important properties of representative metals, metalloids, and nonmetals in the periodic table. Chemistry 2019-02-14T00:00:00Z In general, the combination of a metal and a nonmetal produces a salt. Chemistry 2019-02-14T00:00:00Z As expected, these metals react with both acids and nonmetals to form ionic compounds. Chemistry 2019-02-14T00:00:00Z Nearly all of the nonmetal oxides are acid anhydrides. Chemistry 2019-02-14T00:00:00Z In this regard, these elements resemble nonmetals in their behavior. Chemistry 2019-02-14T00:00:00Z This bonding capability is in contrast to the nonmetal carbon, whose ability to form carbon-carbon bonds gives it prime importance in the plant and animal worlds. Chemistry 2019-02-14T00:00:00Z At higher temperatures, boron reacts with all nonmetals, except tellurium and the noble gases, and with nearly all metals; it oxidizes to B2O3 when heated with concentrated nitric or sulfuric acid. Chemistry 2019-02-14T00:00:00Z Sulfur dioxide dissolves in water to form a solution of sulfurous acid, as expected for the oxide of a nonmetal. Chemistry 2019-02-14T00:00:00Z The acidity of oxyacids requires that the hydrogen atoms bond to the oxygen atoms in the molecule rather than to the other nonmetal atom. Chemistry 2019-02-14T00:00:00Z The nonmetal chlorine is more electronegative than any other element except fluorine, oxygen, and nitrogen. Chemistry 2019-02-14T00:00:00Z Note the background color denotes whether an element is a metal, metalloid, or nonmetal, whereas the element symbol color indicates whether it is a solid, liquid, or gas. Chemistry 2019-02-14T00:00:00Z When atoms of nonmetal elements form ions, they generally gain enough electrons to give them the same number of electrons as an atom of the next noble gas in the periodic table. Chemistry 2019-02-14T00:00:00Z The periodic table can help us recognize many of the compounds that are ionic: When a metal is combined with one or more nonmetals, the compound is usually ionic. Chemistry 2019-02-14T00:00:00Z Generally, the strength of the oxyacid increases with the number of oxygen atoms bonded to the nonmetal atom and not to a hydrogen. Chemistry 2019-02-14T00:00:00Z Whereas ionic compounds are usually formed when a metal and a nonmetal combine, covalent compounds are usually formed by a combination of nonmetals. Chemistry 2019-02-14T00:00:00Z Elements can be classified as metals, metalloids, and nonmetals, or as a main-group elements, transition metals, and inner transition metals. Chemistry 2019-02-14T00:00:00Z Ionic compounds generally form from metals and nonmetals. Chemistry 2019-02-14T00:00:00Z Binary ionic compounds typically consist of a metal and a nonmetal. Chemistry 2019-02-14T00:00:00Z Halides of the metals vary from ionic to covalent; halides of nonmetals are covalent. Chemistry 2019-02-14T00:00:00Z The name of the metal is written first, followed by the name of the nonmetal with its ending changed to –ide. Chemistry 2019-02-14T00:00:00Z Less active metals and the nonmetals give oxides. Chemistry 2019-02-14T00:00:00Z Elemental sulfur oxidizes less electronegative nonmetals, and more electronegative nonmetals, such as oxygen and the halogens, will oxidize it. Chemistry 2019-02-14T00:00:00Z The electronegativity of the nonmetals is greater than that of hydrogen. Chemistry 2019-02-14T00:00:00Z |
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