化学专业英语(修订版)翻译

01 THE ELEMENTS AND THE PERIODIC TABLE

01 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 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，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 \determines its chemical behavior. At present all the atoms from Z = 1 to Z = 107 are known; there are 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= =Mg

Some 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, 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 elements 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 elements 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 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 main 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 table, 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 line—the metalloids-have properties characteristic 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, the 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 group IB —copper, silver, and gold—are 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 reactive as the alkali metals. The group IIB elements—zinc, 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 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 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, 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 arsenic—and 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 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，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