首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
One of the simplest and best known kinds of crystal is the ionic salt, of which a typical example is sodium chloride, or ordinar
One of the simplest and best known kinds of crystal is the ionic salt, of which a typical example is sodium chloride, or ordinar
admin
2020-12-14
50
问题
One of the simplest and best known kinds of crystal is the ionic salt, of which a typical example is sodium chloride, or ordinary table salt. The fundamental components of an ionic salt are ions: atoms or molecules that have become electrically charged by gaining or losing one more electrons. In forming sodium chloride, for example, sodium atoms give up an electron(thereby becoming positively charged)and chlorine atoms gain an electron(thereby becoming negatively charged). The ions are attracted to one another by their opposite charges, and they stack together compactly, like tightly packed spheres. Recently, scientists at Michigan State University created a new kind of crystal called an electride. In electrides, the anions(negative ions)are completely replaced by electrons, which are trapped in naturally formed cavities within a framework of regularly stacked cations(positive ions). Electrides are the first examples of ionic salts in which all these anionic sites are occupied solely by electrons.
Unlike other types of anions, anionic electrons do not behave as if they were
simple
charged spheres. In particular, because of their low mass and their tendency to interact with one another over great distances, they cannot be "pinned down" to any one location. Instead, they wander close to and among the atoms lining the cavity and interact with electrons in nearby cavities, perhaps changing places with them.
The properties of an electride depend largely on the distance between the cavities that hold trapped electrons. When the trapped electrons are far apart, they do not interact strongly, and so behave somewhat like an array of isolated negative charges. When they are closer together, they begin to display properties associated with large ensembles of identical particles. When they are still closer, the ensemble properties dominate and the electrons "delocalize": they are no longer tightly bound within individual cavities but are more or less free to pass through the spaces within the framework of positive ions.
By synthesizing electrides from a variety of materials, one can vary the geometry of the anionic cavities and their relation to the surrounding cations. The resulting properties may make it possible for electrides to become a basis for economically useful new materials and devices. For instance, because the electrons in some electrides are very weakly bound, these crystals could be effective as photosensitive detectors, in which an impinging photon liberates an electron, resulting in a small electric current. The same weak binding could also make electrides useful in solar energy converters and as cathodes in batteries. One obstacle is the tendency of electrides to decompose through reaction with air and water. Researchers are seeking ways to increase their stability.
It can be inferred from the text that anions behaving as "simple charged spheres"(Para.3)could be expected to______.
选项
A、readily lose electrons and become positively charged
B、move freely in and out of their cavities
C、respond to photons by liberating electrons
D、remain fixed relative to their cations
答案
D
解析
推断题。根据第三段内容.大意是“和其他类型的阴离子不同,作为阴离子的电子不像那些简单的带电球体。它们很特别,由于它们的质量很小而且有与远距离的离子进行相互作用的倾向。它们不会被固定在任何一个位置。相反,它们会到处游离,或者紧靠那些在空穴边上的原子,或者在这些原子之间游离,并且还和附近空中的电子发生相互作用,甚至还可能与它们交换位置。”可知那些简单的带电球体的阴离子会被固定,不会到处游离,和选项D的表述一致,所以答案是D。
转载请注明原文地址:https://kaotiyun.com/show/e8P7777K
0
大学英语六级
相关试题推荐
Who’sReallyAddictingYoutoTechnology?[A]"NearlyeveryoneIknowisaddictedinsomemeasuretotheInternet,"wroteTonyS
Manycurrentdiscussionsofimmigrationissuestalkaboutimmigrantsingeneral,asiftheywereabstractpeopleinanabstract
A、Failureinreadingmedicinedirections.B、Incapabilityoftakingcareofchildren.C、Brokenfamilyrelationship.D、Reluctance
A、Thesenetworksdonothavehugepotential.B、Mostconnectionsbetweenpeoplecannotbeseen.C、Peopledonotknowhowsocialn
A、Byfindingsufficientsupportforimplementation.B、Bytakingintoaccounttheirownabilitytochange.C、Byconstantlykeepin
A、DifferentexperiencesinEurope.B、Differentsocialandsportorganizations.C、Differentmajorsinyourcollege.D、Differentp
A、TheimportantrolethatInternetplaysinhumanlife.B、TheadvantagesoftheInternetandthecomputer.C、Theinfluenceofth
A、Theinternshipprogramdoesnotofferstudentsout-of-classroomexperiences.B、Thecooperativeeducationprogramprovideslong
Carmakershavelongusedsextoselltheirproducts.Recently,however,bothBMWandRenaulthavebasedtheirlatestEuropeanm
随机试题
铣床加工精度为IT9~IT7,表面粗糙度Ra能达到()。
甲公司是一家机械加工企业,产品生产需要某种材料,年需求量为720吨(一年按360天计算)。该公司材料采购实行供应商招标制度,年初选定供应商并确定材料价格,供应商根据甲公司指令发货,运输费由甲公司承担。目前有两个供应商方案可供选择,相关资料如下:方
对一些不够理智、不时冲动的游客,导游应采取的办法是进行劝导。()
股市波动信息对一些投资者来说价值连城,对另外一些投资者来说却毫无意义,这体现了()。
根据所给资料,回答下列问题。2014年,某自主创新示范区输出境内的技术合同总数为11456项,技术合同成交额为211.92亿元,分别占全市输出境内的47.55%和49.66%。该示范区输出境内合同中,上述五类技术领域的输出境内合同总数约占:
甲、乙两个科室各有4名职员,且都是男女各半。现从两个科室中选出4人参加培训,要求女职员比重不得低于一半,且每个科室至少选1人。问有多少种不同的选法?()
根据以下资料,回答下列小题。2012年,国家旅游局旅游业管理与服务支出约为住房改革支出的()倍。
Writeshortnoteson:(a)Realproperty.(b)Personalproperty.
RestrictingtheproblemofThirdWorldcountriestohungeralone—althoughnotallpeoplewholiveinpovertyarepermanentlysta
Culturaltendenciesimpactthewaychildrenparticipateineducation.Therearedifferentexpectationsabout"normal"schoolb
最新回复
(
0
)