化学专业英语修订版翻译.docx

1、化学专业英语修订版翻译化学专业英语(修订版)翻译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

2、is 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

3、质量数，A。在一个原子中的中子数量等于A Z的数量。of an element, numerous 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 elemen

4、ts are periodic functions of their atomic numbers. 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 el

5、ements having similar properties placed in vertical 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

6、式是有可能的。像这样的排列叫元素周期表。Each horizontal row of elements 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

7、 includes 32 elements, and the last period is apparently 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 mai

8、n group elements, and the members of the other 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 t

9、able, a heavy stepped line divides the elements 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 character

10、istic of - both metals and nonmetals. It may be 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, t

11、he elements of group IA make up the alkali metal 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 g

12、roup IB copper, silver, and goldare comparatively 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

13、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

14、 reactive as the alkali metals. The group IIB elementszinc, 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

15、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 o

16、xide on the surface, which protects the bulk of 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

17、+的电荷。IIIA由金属钪，钇，镧系和锕系元素组成。Group IVA consists of 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 tetrachlorid

18、e, CCl4. The group IVB metals titanium, zirconium, 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

19、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 elements 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, phosphide

20、s, and arsenides in which ions having charges of 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

21、，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-

22、. The elements of group A are all nonmetals and 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

23、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 o

24、f the behavior of the respective groups. B，B，和VIIIB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

25、metallic character, eventually becoming nonmetals, 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 ELEMENT

26、S02非金属元素We noted earlier that -nonmetals exhibit 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

27、 melting and boiling points. Their molecular structures, 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

28、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)

29、 whose vapor pressures also indicate small intermolecular 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 Nonmetals

30、Diatomic MoleculesMolecular WeightMelting Point 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 con

31、trast to the first members of these groups, N2 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 th

32、e third period and higher do not allow good parallel 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 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