《化学专业英语(修订版)翻译(28页).doc》由会员分享，可在线阅读，更多相关《化学专业英语(修订版)翻译(28页).doc（27页珍藏版）》请在taowenge.com淘文阁网|工程机械CAD图纸|机械工程制图|CAD装配图下载|SolidWorks_CaTia_CAD_UG_PROE_设计图分享下载上搜索。
1、-化学专业英语(修订版)翻译-第 27 页01 THE ELEMENTS AND THE PERIODIC TABLE01 元素和元素周期表The number of protons in the nucleus of an atom is referred to as the atomic number, or proton number, Z. The number of electrons in an electrically neutral atom is also equal to the atomic number, Z. The total mass of an atom is
2、determined very nearly by the total number of protons and neutrons in its nucleus. This total is called the mass number, A. The number of neutrons in an atom, the neutron number, is given by the quantity A-Z. 在一个原子核中的质子数量被称为原子序数，或质子数，Z。在一个电中性原子中的电子数量也等于原子序数，Z。一个原子的总质量被测定是非常接近于原子核中质子和中子的总数。这个总数被称为质量数
3、，A。在一个原子中的中子数量等于A Z的数量。The term element refers to, a pure substance with atoms all of a single kind. To the chemist the kind of atom is specified by its atomic number, since this is the property that determines its chemical behavior. At present all the atoms from Z = 1 to Z = 107 are known; there ar
4、e 107 chemical elements. Each chemical element has been given a name and a distinctive symbol. For most elements the symbol is simply the abbreviated form of the English name consisting of one or two letters, for example: 这个术语(指chemical element)也可以指由相同质子数的原子组成的纯化学物质。对化学家来说，这类原子通过原子数来说明，因为它的性质是决定其化学行
5、为。目前，从Z = 1 到Z = 107的所有原子是知道的；有107种化学元素。每一种化学元素起了一个名字和独特的象征。对于大多数元素都仅仅是一个象征的英文名称缩写形式，由一个或两个字母组成，例如：oxygen=O nitrogen = N neon=Ne magnesium = Mg 氧= =O 氮 = = N氖= = Ne 镁= =MgSome elements,which have been known for a long time,have symbols based on their Latin names, for example: 很久以来就已经知道一些元素，根据他们的拉丁名字
6、符号命名，例如：iron=Fe(ferrum) copper=Cu(cuprum) lead=Pb(plumbum) 铁= =铁(铁) 铜= =铜(铜) 铅= =铅(铅)A complete listing of the elements may be found in Table 1. 一个完整的元素可以在表1中被发现。Beginning in the late seventeenth century with the work of Robert Boyle, who proposed the presently accepted concept of an element, numero
7、us investigations produced a considerable knowledge of the properties of elements and their compounds1. In 1869, D.Mendeleev and L. Meyer, working independently, proposed the periodic law. In modern form, the law states that the properties of the elements are periodic functions of their atomic numbe
8、rs. In other words, when the elements are listed in order of increasing atomic number, elements having closely similar properties will fall at definite intervals along the list. Thus it is possible to arrange the list of elements in tabular form with elements having similar properties placed in vert
9、ical columns2. Such an arrangement is called a periodic.早在十七世纪末期，罗伯特波义耳就开始了这项工作，他提出了现在公认的元素的概念，大量的研究使我们对元素及其化合物的性质有了相当的了解。在1869年，门捷列夫和迈耶，独立工作，提出了元素周期律。用现代方式，元素周期律阐述了元素的特性原子序数的周期性函数。换句话说，当按原子序数增加的顺序排列元素，具有相近特性的元素将沿着列表以一定的间隔下降。因此，将具有类似性质的元素排成纵列，从而把元素排成表格形式是有可能的。像这样的排列叫元素周期表。Each horizontal row of elem
10、ents constitutes a period. It should be noted that the lengths of the periods vary. There is a very short period containing only 2 elements, followed by two short periods of 8 elements each, and then two long periods of 18 elements each. The next period includes 32 elements, and the last period is a
11、pparently incomplete. With this arrangement, elements in the same vertical column have similar characteristics. These columns constitute the chemical families or groups. The groups headed by the members of the two 8-element periods are designated as main group elements, and the members of the other
12、groups are called transition or inner transition elements. 每个水平排的元素构成一个周期。但应该注意的是，周期长度会发生改变。非常短的周期只包含二元素，后面跟着两个8个元素短周期，然后是两个由18个元素组成的长周期。下一个周期包括32个元素，最后一个周期明显是不完整的。按照这样的安排，在同一垂直栏的元素有相似的特点。这些垂直栏构成化学族。两个8个元素的周期组成的元素被认为是主族元素，其他族的元素被称为过渡元素。In the periodic table, a heavy stepped line divides the elements
13、 into metals and nonmetals. Elements to the left of this line (with the exception of hydrogen) are metals, while those to the right are nonmetals. This division is for convenience only; elements bordering the linethe metalloids-have properties characteristic of - both metals and nonmetals. It may be
14、 seen that most of the elements, including all the transition and inner transition elements, are metals. 在元素周期表，阶梯线将元素分成金属和非金属元素等。阶梯线左边的元素(除氢)是金属，右边的是非金属元素等。这个分割仅为方便使用；元素分界线上的元素准金属具有金属和非金属的特性。这可以看出，大部分的元素，包括所有的过渡和内在过渡元素，是金属。Except for hydrogen, a gas, the elements of group IA make up the alkali meta
15、l family. They are very reactive metals, and they are never found in the elemental state in nature. However, their compounds are widespread. All the members of the alkali metal family, form ions having a charge of 1+ only. In contrast, the elements of group IB copper, silver, and goldare comparative
16、ly inert. They are similar to the alkali metals in that they exist as 1+ ions in many of their compounds. However, as is characteristic of most transition elements, they form ions having other charges as well. 除了氢气，IA由碱金属元素组成。他们是非常活泼的金属，在自然界中，它们从没有以元素态形式出现。然而，他们的化合物是广泛存在的。所有的碱金属离子仅有1+的电荷。相比之下，IB 铜，银
17、和金是惰性的。在他们的许多化合物他们存在1+离子，这与碱金属离子是相似的。然而，像许多过渡元素所具有的特点一样，他们也形成具有其他电荷的离子。The elements of group IIA are known as the alkaline earth metals. Their characteristic ionic charge is 2+. These metals, particularly the last two members of the group, are almost as reactive as the alkali metals. The group IIB e
18、lementszinc, cadmium, and mercury are less reactive than are those of group II A5, but are more reactive than the neighboring elements of group IB. The characteristic charge on their ions is also 2+. IIA的元素被称为碱土金属。其特点是离子电荷2+。这些金属，特别是最后两个元素，几乎具有与碱金属一样的反应活性。IIB元素，锌，镉，汞比IIA的元素具有更少的反应活性，但是比相邻的IB的元素有更强的反
19、应活性。IB的元素离子的特征电荷也是2+。With the exception of boron, group IIIA elements are also fairly reactive metals. Aluminum appears to be inert toward reaction with air, but this behavior stems from the fact that the metal forms a thin, invisible film of aluminum oxide on the surface, which protects the bulk of
20、 the metal from further oxidation. The metals of group IIIA form ions of 3+ charge. Group IIIB consists of the metals scandium, yttrium, lanthanum, and actinium. 除了硼、IIIA元素也是具有相当强活性金属。在空气中铝似乎惰性的，但这种行为的根源是金属表面形成了一层薄的、不可见的氧化铝膜，这层膜保护大量的金属的进一步氧化。IIIA金属离子具有3+的电荷。IIIA由金属钪，钇，镧系和锕系元素组成。Group IVA consists of
21、 a nonmetal, carbon, two metalloids, silicon and germanium, and two metals, tin and lead. Each of these elements forms some compounds with formulas which indicate that four other atoms are present per group IVA atom, as, for example, carbon tetrachloride, CCl4. The group IVB metals titanium, zirconi
22、um, and hafnium also forms compounds in which each group IVB atom is combined with four other atoms; these compounds are nonelectrolytes when pure. IVA元素由一个非金属，碳、两个准金属，硅和锗，和两个金属，锡和铅组成。按照配位规则，这些元素的每一种形成一些化学物，这表明每一个IVA原子需要四个其他原子配位，例如，四氯化碳CCl4。IVB金属钛、锆、和铪也形成化合物，其中每个IVB原子结合四个其他原子；这些化合物的纯物质是非电解质。The elem
23、ents of group V A include three nonmetals nitrogen, phosphorus, and arsenicand two metals antimony and bismuth. Although compounds with the formulas N2O5, PCl5, and AsCl5 exist, none of them is ionic. These elements do form compounds-nitrides, phosphides, and arsenides in which ions having charges o
24、f minus three occur. The elements of group VB are all metals. These elements form such a variety of different compounds that their characteristics are not easily generalized. VA元素包括三种非金属-氮、磷、砷，和两种金属锑和铋。尽管物质N2O5，PCl5，AsCl5存在，但是其中没有一个是离子。这些元素能形成化合物氮化物，磷化物，和砷化物其中离子带3-价的负电荷。VB的元素都是金属。这些元素形成各种不同的化合物，它们的特
25、性不容易归纳。With the exception of polonium, the elements of group VIA are typical nonmetals. They are sometimes known, as the, chalcogens, from the Greek word meaning ash formers. In their binary compounds with metals they exist as ions having a charge of 2-. The elements of group A are all nonmetals and
26、 are known as the halogens. from the Greek term meaning salt formers. ” They are the most reactive nonmetals and are capable of reacting with practically all the metals and with most nonmetals, including each other. 除了钋的元素，VIA族元素是典型的非金属。他们是众所周知的硫族元素，这来自于希腊字母，词意是“灰的创造者”。在他们与金属离子形成的二元化合物中离子带2-价的电荷。A族的
27、元素都是非金属，被称为卤素，来自希腊术语，意即“盐的创造者”。他们是最具有反应活性的非金属，能够与所有的金属和大多数非金属反应，包括互相之间的反应。The elements of groups B, B, and VIIIB are all metals. They form such a wide Variety of compounds that it is not practical at this point to present any examples as being typical of the behavior of the respective groups. B，B，和V
28、IIIB族元素都是金属。它们形成了各种各样的化合物，在这一点上我们甚至不能举出任何能表现各族元素典型变化的例子。The periodicity of chemical behavior is illustrated by the fact that， excluding the first period, each period begins with a very reactive metal. Successive element along the period show decreasing metallic character, eventually becoming nonmeta
29、ls, and finally, in group A, a very reactive nonmetal is found. Each period ends with a member of the noble gas family. 除了第一个周期，化学行为的周期性可以用事实说明，每一个周期以一个非常活泼的金属开始。沿着周期元素显示出了逐渐减少的金属性，最终成为非金属，最后，在A族，可以发现一个很活泼的非金属元素。每一个周期的结尾是一个稀有气体元素。02 THE NONMETAL ELEMENTS02非金属元素We noted earlier that -nonmetals exhibi
30、t properties that are greatly different from those of the metals. As a rule, the nonmetals are poor conductors of electricity (graphitic carbon is an exception) and heat; they are brittle, are often intensely colored, and show an unusually wide range of melting and boiling points. Their molecular st
31、ructures, usually involving ordinary covalent bonds, vary from the simple diatomic molecules of H2, Cl2, I2, and N2 to the giant molecules of diamond, silicon and boron. 很早我们就已经注意到非金属表现出了与金属不一样的特性。一般来说，非金属是比较差的电子（石墨碳除外）和热的导体；他们是易碎的，通常具有较强的颜色，并表现出很宽范围的熔点和沸点。他们的分子结构，通常是包括了普通的共价键，从简单的双原子分子的H2，Cl2，I2和N2
32、到钻石、硅和硼的大分子。The nonmetals that are gases at room temperature are the low-molecular weight diatomic molecules and the noble gases that exert very small intermolecular forces. As the molecular weight increases, we encounter a liquid (Br2) and a solid (I2) whose vapor pressures also indicate small inte
33、rmolecular forces. Certain properties of a few nonmetals are listed in Table 2. 在室温下是气相的非金属是低分子质量的双原子分子和施加了非常小的分子间作用力的稀有气体。随着分子量的增大，我们遇到了一个液体(Br2)和一个固体(I2)，其蒸气压也表明小的分子间作用力。一些非金属的某些性质列在表2中。Table 2 Molecular Weights and Melting Points of Certain NonmetalsDiatomic MoleculesMolecular WeightMelting Point
34、 CColorH22-239.1NoneN228-210NoneF238-223Pale yellowO232-218Pale blueCl271-102Yellow greenBr2160-7.3Red brownI2254113GrayblackSimple diatomic molecules are not formed by the heavier members of Groups V and VI at ordinary conditions. This is in direct contrast to the first members of these groups, N2
35、and O2. The difference arises because of the lower stability of bonds formed from p orbitals of the third and higher main energy levels as opposed to the second main energy level2. The larger atomic radii and more dense electron clouds of elements of the third period and higher do not allow good par
36、allel overlap of p orbitals necessary for a strong bond. This is a general phenomenon strong bonds are formed only between elements of the second period. Thus, elemental nitrogen and oxygen form stable molecules with both and bonds, but other members of their groups form more stable structures based
37、 on bonds only at ordinary conditions. Note3 that Group VII elements form diatomic molecules, but bonds are not required for saturation of valence. 通常情况下，V和VI族包括的更重的元素不能形成简单的双原子分子。这与这两个族中所包括的第一种元素是直接相反的，N2和O2。差别的出现是由于与第二主能级相反，第三和更高主能级的p轨道形成的键稳定性较低。第三和更高周期元素的更大的原子半径和更密的电子云不允许一个强的键所必需的p轨道很好的平行重叠。这是一个普
38、遍的现象强的键仅仅在第二周期的元素之间形成。因此，氮和氧元素形成了具有和键的稳定分子，但是在通常情况下，这两个族的其他元素可以形成仅仅基于键的更稳定的结构。需要注意的是第VII族元素形成了双原子分子，但是键不需要用于价态的饱和。Sulfur exhibits allotropic forms. Solid sulfur exists in two crystalline forms and in an amorphous form. Rhombic sulfur is obtained by crystallization from a suitable solution, such as C
39、S2, and it melts at 112C. Monoclinic sulfur is formed by cooling melted sulfur and it melts at 119C. Both forms of crystalline sulfur melt into S-gamma, which is composed of S8 molecules. The S8 molecules are puckered rings and survive heating to about 160C. Above 160C, the S8 rings break open, and
40、some of these fragments combine with each other to form a highly viscous mixture of irregularly shaped coils. At a range of higher temperatures the liquid sulfur becomes so viscous that it will not pour from its container. The color also changes from straw yellow at sulfurs melting point to a deep r
41、eddish-brown as it becomes more viscous. 硫具有同素异形体。固态硫存在两种晶形和一种无定形的形式。斜方硫通过在合适的溶液中结晶化获得，如CS2，在112C时融化。单斜硫通过冷却融化的硫获得和单斜硫在119C时融化。两种形式的晶体硫融化成S-gamma，它由S8分子组成。S8的分子起皱成环和加热到160C仍然存在。超过160C， S8环被破坏，其中的一些片段相互结合形成一个高粘度的形状不规则的混合物。在更高的温度范围液态硫变得黏度很高，以致于在容器中不能倒出。随着变得更粘稠，其颜色也从硫熔点时的稻草黄色变成红褐色。As4 the boiling point
42、 of 444 C is approached, the large-coiled molecules of sulfur are partially degraded and the liquid sulfur decreases in viscosity. If the hot liquid sulfur is quenched by pouring it into cold water, the amorphous form of sulfur is produced. The structure of amorphous sulfur consists of large-coiled
43、helices with eight sulfur atoms to each turn of the helix; the overall nature of amorphous sulfur is described as3 rubbery because it stretches much like ordinary rubber. In a few hours the amorphous sulfur reverts to small rhombic crystals and its rubbery property disappears. 随着接近444C的沸点，硫的大的螺旋状分子被
44、部分降解和液态硫的黏度降低。如果把热的液态硫倒入到冷却水里骤冷，就会产生无定形硫。无定形硫的结构由具有8个硫原子的大的螺旋线组成；无定形硫的总特性被描述成是有弹性的，因为它可以类似于普通的橡胶伸张。几个小时之内无定形硫恢复成菱形晶体，和它的弹性性质消失。Sulfur, an important raw material in industrial chemistry, occurs as the free element, as SO2 in volcanic regions, as H2S in mineral waters, and in a variety of sulfide ores
45、 such as iron pyrite FeS2, zinc blende ZnS, galena PbS and such, and in common formations of gypsum CaSO4 2H2O, anhydrite CaSO4, and barytes BaSO4 2H2O. Sulfur, in one form or another, is used in large quantities for making sulfuric acid, fertilizers, insecticides, and paper. 硫在工业化学中是一种重要的原材料，它以单质，在
46、火山区域以SO2，在矿泉水中H2S，和各种硫化物出现，像黄铁矿FeS2，闪锌矿ZnS，方铅矿PbS等等，还有石膏CaSO42H2O，硬石膏CaSO4，以及重晶石BaSO42H2O等普通形态。硫或以某种方式，用于大量制造硫酸、肥料、杀虫剂、和纸张。Sulfur in the form of SO2 obtained in the roasting of sulfide ores is recovered and converted to sulfuric acid, although in previous years much of this SO2 was discarded through
47、 exceptionally tall smokestacks. Fortunately, it is now economically favorable to recover these gases, thus greatly reducing this type of atmospheric pollution. A typical roasting reaction involves the change: 2 ZnS + 3 O22 ZnO + 2 SO2在硫化物煅烧中获得的以SO2形式存在的硫被转化成硫酸，尽管在过去几年许多二氧化硫通过高烟囱排放出去。幸运的是，现在回收这些气体的成
48、本是较低的，从而这可以大幅度地减少大气污染。典型的焙烧反应如下：2 ZnS + 3 O2-2氧化锌+ 2二氧化硫Phosphorus, below 800 consists of tetratomic molecules, P4. Its molecular structure provides for a covalence of three, as may be expected from the three unpaired p electrons in its atomic structure, and each atom is attached to three others6. Instead of a strictly orthogonal orientation, with the three bonds 90 to each other, the bond angles are only 60. This supposedly strained structure is stabilized by the mutual interaction of the four atoms (each atom is bonded to the other three), b