应用化学专业英语课文翻译

1 3 THE PERIODIC LAW 周期律 In 1869 Dmitri Ivanovitch Mendeleev 1834 1907 of Russia and Lothar Meyer 1830 1895 of Germany independently published their periodic arrangements of the elements Both of these periodic arrangements were based on increasing atomic weights 译 1869 年 俄罗斯的德米特里 伊万诺维奇门捷列夫 1834 年至 1907 年 和德国的洛萨迈耶 1830 至 1895 年 独立地出版了他们对元素的定期安排 这两个周期的安排都是以原子量的增加为基础的 At the time of Mendeleev s periodic table about 63 elements were known The brilliance and foresightedness of this work can be seen by the fact that Mendeleev left spaces between certain elements in his original table and predicted that these spaces would be filled by the discovery of new elements He left a space for an undiscovered element after calcium and called the element eka boron another space was left under aluminum which he called eka aluminum and another space under silicon which he called eka silicon The term eka comes from Sanskrit meaning one which Mendeleev used to indicate that the missing element was one place away in his table from the element indicated Mendeleev even went so far as to predict with high accuracy the physical and chemical properties of those elements yet to be discovered The three elements above were in fact discovered within his lifetime Scandium atomic number 21 was discovered in 1879 by Lars F Nilson 1840 1899 of Sweden and was found to correspond in properties to eka boron gallium 31 was discovered in 1875 by Lecoq de Baisbaudran 1832 1912 and was found to correspond to eka aluminum and ger manium 32 was discovered in 1886 by C A Winkler 1838 1904 and was found to correspond to eka silicon The amazing way in which Mendeleev s predictions were fulfilled is illustrated in Table 1 2 which compares the predicted properties of eka silicon with those of germanium 译 在门捷列夫的周期表中 大约有 63 种元素是众所周知的 事实上 门捷列 夫在他表中已确定的元素中留有空位并且预测这些空位会被以后发现的新元素 填满 由此可见这项工作的辉煌和前瞻性 他在钙的后面留了一个空位给未知元素并称之为准硼 在铝的下面留了一个空 位并称之为准铝 在硅的下面留了一个空位并称之为准硅 术语 准 来自梵文 意思是 之一 是门捷列夫用来表示他表中指定元素 中缺失的一个地方的元素 门捷列夫甚至高精确度地预测了目前为止仍未被发 现的元素的物理性质和化学性质 事实上 上面提到的三个元素在他有生之年 就已经被发现了 钪 原子序号 21 在 1879 年被瑞典的 Lars F Nilson 1840 1899 所发现 并证实它的属性符合硼 镓 31 在 1875 年被 Lecoq de Baisbaudran 1832 1912 发现 并证实它的属性符合铝 锗 32 在 1886 年被 C A Winkler 1838 1904 发现 并证实它的属性符合硅 门捷 列夫的预测以一种惊人的方式实现了 如表 1 2 比较了准硅预测的那些性质 和锗的性质 Mendeleev constructed his table by arranging the elements in order of increasing atomic weights The elements were tabulated so that those with similar chemical properties fitted into columns to form family groups This arrangement left vacant spaces for undiscovered elements 译 门捷列夫通过以原子量增加的顺序来安排元素构建他的表 那些化学性质 相似的元素被制成列表 形成了族 这样的安排给未被发现的元素留了空置空 间 Several modifications have been made to Mendeleev s table First a new family of elements the noble gases was discovered and added to the table Also it was observed that when the elements were listed according to increasing atomic weights several discrepancies arose in the table In the present table for example argon appears before potassium even though the atomic weight of argon is greater than that of potassium There is no mistaking that potassium should come after argon because argon is certainly one of the noble gases and potassium behaves like the other alkali metals There are two other places in the table where this type of deviation occurs 译 门捷列夫的表已经做了若干次修改 首先 一个新的元素族 稀有气体 已经被发现并添加到表中 其次 可观察到元素根据原子质量的增加被列出 一些差异呈现在表中 在现在的元素表中 例如 氩出现在钾前面 尽管氩的 原子质量比钾更大 钾在氩的后面并没有错误 因为氩确实是稀有气体的一类 并且钾的性质类似于其它碱金属 在元素表中 还有其它两个地方也有类似的 偏差 The correct order of the elements was resolved by the British physicistH G J Moseley 1887 1915 who while studying the X ray emission frequencies of the elements established that the elements should be arranged in order of increasing charge on their nuclei namely the atomic number This correction nullified the above mentioned discrepancies and led to the current statement of the Periodic Law This law states that properties of the elements are periodic functionstheir atomic numbers In this sense periodic means some regular cycle With the discovery of isotopes for many the elements it became more apparent that the atomic number is the correct basis for periodicity 英国物理学家 H G J Moseley 1887 1915 解决了元素的正 确排列顺序的问题 当他研究元素的 x 射线发射频率时建立下面的 理论 元素应该按照它们核电荷增加的顺序排列 也叫做原子序数 这种修正消除上述的矛盾 形成元素周期律现在的表示形式 元素 周期律声称 元素的周期性与原子序数有关 这种意义上说 周期 的意味着以一定的循环重现 随着许多元素的同位素的发现 越来 越彰显原子序数是周期性的正确基础 As one studies the format of the periodic table it becomes evident that the periodicity in the properties of the elements is due to the recurring similarities of their electron structures 当人们研究周期表的格式时 可以非常明显的看出元素性质的周 期性是因为它们电子结构的相似 The most commonly used periodic table is the long form In this table the elements are arranged horizontally in numerical sequence according to their atomic numbers the result is seven horizontal periods Each period with the exception of the first starts with an alkali metal and ends with a noble gas By this arrangement vertical columns of elements are formed having identical or similar outer shell electron structure and thus similar chemical peoperties These columns are known as groups or families of elements 在元素周期表中最常见的是长排 在周期表中 元素按照原子序 数以一定的水平顺序排列 结果形成 7 个水平周期 除第一个外 每个周期从碱金属开始 以稀有气体结束 这种排列 形成纵行 每个纵行具有相同或相似的外层电子结构 因此具有相似的化学性 质 这些纵行被人们称为元素的族 The heavy zigzag line starting at boron and running diagonally down the table separates the elements into metals and nonmetals The elements to the right of the line are nonmetals and those to the left are metallic The elements bordering the zigzag line are the metalloids and show both metallic and nonmetallic properties With some exceptions the characteristic electronic arrangement of metals is that their atoms have one two or three electrons in their outer energy level while nonmetals have five six and seven electrons in their outer energy level 从硼开始 沿着周期表对角走的 Z 型粗线将金属和非金属隔开 线的 右边是非金属 线的左边是金属 靠近 Z 型线的元素是过渡金属 既具 有金属也具有非金属的性质 除了一些特例 金属的特征电子结构是 它们的最外电子层具有一个 两个或者三个电子 而非金属最外层则 有五个 六个或者七个电子 It is interesting to note that with this periodic arrangement the elements fall into blocks according to the sublevel of electrons that are being filled in their atomic structure The s block comprising groups A and A have one or two s electrons in their outer energy level The p block includes groups A to A and the noble gases except helium in these elements electrons are filling the p sublevel orbitals The d block includes the transition elements of groups B to B and group The d sublevel of electrons are being filled in these elements The f block of elements include the inner transition series In the lanthanide series electrons are filling the 4 f sublevel in the actinide series electrons are filling the 5 f sublevel 有趣的是 这一周期性排列的元素分成区域 根据填充的亚层电子 原子结构 由 A 和 A 主族组成 s 区 它们外层能级具有 1 个电子 或 2 个 s 电子 p 区包括组 A 到 A 主族和稀有气体 氦除外 这些元素的电子填充在 p 亚层轨道 d 区包括过渡元素 B 到 B 到 这些元素中 d 轨道被填充 元素的 f 区包括内过渡系列 在 镧系中 电子填充 4 f 亚层 在锕系元素中 电子填充 5f 亚层 The periodic table has been used for studying the relationships of many properties of the elements Ionization energies densities melting points atomic radii atomic voiumes oxidation states electrical conductance and electronegativity are just a f