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1、精选优质文档-倾情为你奉上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
2、83;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 origina
3、l 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
4、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 ye
5、t 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 (
6、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 proper
7、ties 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
8、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
9、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 M
10、endeleev'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 be
11、fore 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
12、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
13、),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 La
14、w.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.Mose
15、ley(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
16、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
17、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 a
18、re 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
19、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 a
20、toms 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
21、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 groupsA andA have one or two s electrons in their outer energy level.The p block includes groups A toA and the noble
22、 gases(except helium).in these elements electrons are filling the p sublevel orbitals. The d block includes the transition elements of groupsB 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
23、 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
24、 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 few mentioned.however,a detailed discussion of these properties is not p
25、ractical at this time.the periodic table is not a pancacea for the chemist,but it is an important correlating unit for tying together the properties and relationships of the elements.in the past, the use of the periodic table for predicting the existence of certain elements was invaluable to their d
26、iscovery.today the periodic table is still being used too predict the probably synthesis of new elements.a thorough understanding of chemical periodicity can lead to a better insight regarding the properties of the elements.。周期表用于研究很多性质的元素的关系，电离能、密度、熔点、原子半径,原子数量,氧化状态、电导性、电负性只是研究当中的一部分，这些性质的详细讨论现在还没有条件实现，元素周期表不是化学的万能的工具，它对于联系属性和元素的关系非常重要。在过去，周期表用于预测未知元素存在是起非常重要的作用，今天，周期表仍然用于预测可能的新元素的合成。透彻地了解化学周期可以更好地了解有关的元素的属性。专心-专注-专业