章节大纲

  • Three elements: A is copper wire, B is silicon carbide, C is neon sign.

    Look at substances A–C in the photos above. They look very different from one another, but they have something important in common. All three are , or pure substances. Can you identify which elements they are? For ideas, listen to the amazing elements song below. The singer rapidly names all of the known elements while pictures of the elements flash by. Even if the video doesn’t help you name the elements pictured above, it will certainly impress you with the need to organize the large number of elements that have been discovered.
    ::在以上照片中查看物质 A-C 。 它们看起来彼此非常不同, 但有重要共同点。 这三个物质都是或纯物质。 您能辨别它们是什么元素吗? 对于想法, 请听下面的惊人元素歌曲。 歌手快速命名所有已知元素, 而元素闪烁的图片则被快速命名。 即使视频无法帮助您点出上面所描绘的元素, 但它肯定会使您感到有必要组织大量已经发现的元素。

    The First Periodic Table
    ::第一次定期表格

    In the 1860s, a scientist named Dmitri Mendeleev also saw the need to organize the elements. He created a table in which he arranged all of the elements by increasing atomic mass from left to right across each row. When he placed eight elements in each row and then started again in the next row, each column of the table contained elements with similar properties. He called the columns of elements groups. Mendeleev’s table is called a periodic table and the rows are called periods. That’s because the table keeps repeating from row to row, and periodic means “repeating.”
    ::1860年代,一位名叫Dmitri Mendeleev的科学家也认为有必要组织元素。他创建了一个表格,通过将原子质量从左到右每行增加一次原子质量来排列所有元素。当他将八个元素放在每行中,然后在下一行重新开始时,表格的每列都包含类似属性的元素。他调用元素组的列。门捷列夫的表格被称为定期表格,行被称为时间段。这是因为表格逐行重复,周期意味着“重复 ” 。

    The Modern Periodic Table
    ::现代定期表格

    A periodic table is still used today to organize the elements. You can see a simple version of the modern periodic table in the Figure . The modern table is based on Mendeleev’s table, except the modern table arranges the elements by increasing instead of atomic mass. Atomic number is the number of in an , and this number is unique for each element. The modern table has more elements than Mendeleev’s table because many elements have been discovered since Mendeleev’s time. 
    ::今天仍使用一个周期表来组织元素。您可以看到图中现代周期表的简单版本。现代表格以门捷列夫的表格为基础,除了现代表格通过增加而不是原子质量来安排元素之外,现代表格通过增加而不是原子质量来安排元素。原子数是一个元素的数量,而每个元素的这个数量是独一无二的。现代表格比门捷列夫的表格有更多的元素,因为自门捷列夫时代以来已经发现了许多元素。

    A modern periodic table displaying elements organized by increasing atomic number.

     

    Reading the Table
    ::阅读表格

    In the Figure , each element is represented by its chemical symbol, which consists of one or two letters. The first letter of the symbol is always written in upper case, and the second letter—if there is one—is always written in lower case. For example, the symbol for copper is Cu. It stands for cuprum , which is the Latin word for copper. The number above each symbol in the table is its unique atomic number. Notice how the atomic numbers increase from left to right and from top to bottom in the table.
    ::在图中,每个元素用化学符号表示,化学符号由一两个字母组成。符号的第一个字母总是用大写字母写,第二个字母(如果有一个字母)总是用小写字母写。例如,铜的符号是Cu。铜的符号是Cu。铜的符号是Cuprum,是铜的拉丁词。表格中每个符号上方的数字是其独有的原子编号。注意表格中原子数字从左到右、从上到下是如何增加的。

    Q: Find the symbol for copper in the Figure . What is its atomic number? What does this number represent?
    ::问题:在图中查找铜的符号。它的原子编号是什么?这个数字代表什么?

    A: The atomic number of copper is 29. This number represents the number of protons in each atom of copper. (Copper is the element that makes up the coil of wire in photo A of the opening sequence of photos.)
    ::A:铜原子序号为29,这个数字代表了每个铜原子质子的数量。 (Copper是照片开端序列照片A中线圈的元素。 )

    Periods of the Modern Periodic Table
    ::现代定期表格的时期

    Rows of the modern periodic table are called periods , as they are in Mendeleev’s table. From left to right across a period, each element has one more proton than the element before it. Some periods in the modern periodic table are longer than others. For example, period 1 contains only two elements: hydrogen (H) and helium (He). In contrast, periods 6 and 7 are so long that many of their elements are placed below the main part of the table. They are the elements starting with lanthanum (La) in period 6 and actinium (Ac) in period 7. Some of the elements in period 7 have recently been discovered and named. The number of each period represents the number of levels that have electrons in them for atoms of each element in that period. In December 2015, the International Union of Pure and Applied Chemistry (IUPAC) verified the existence of four new elements 113, 115, 117, and 118 and approved their addition to the periodic table. These elements complete period 7 of the periodic table.
    ::现代周期表列的行称为时间段, 如在门捷列夫的表格中。 从左到右, 每个元素比其面前的元素多出一个质子。 现代周期表中的有些时期比其他时间长。 例如, 1 周期只包含两个元素: 氢( H) 和 ( He)。 相反, 6 和 7 周期太长, 以至于其元素中有许多元素被置于表格的主要部分之下。 这些元素是从6 周期的lanthanum( La) 开始的元素和7 周期的( Ac) 开始的元素。 7 期的某些元素最近被发现并被命名。 每个时期的数量代表了该时期每个元素的原子电量 。 2015年12月, 国际理论和应用化学联合会(IUPAC) 核实了四个新元素 113、 115、 117 和 118 的存在, 并批准将其添加到周期表 。 这些元素完成了周期表 的 7 周期表 。

    Here are the new element names and their origins:
    ::以下是新元素名称及其起源:

    • Element 113 was named Nihonium, symbol Nh, proposed by Japanese researchers after the Japanese word Nihon, which means Japan.
      ::元素113被命名为Nihonium, 符号Nh, 由日本研究人员提出, 以日文为日文, 意思是日本。
    • A team of scientists from Russia and the United States named element 115, Moscovium, symbol Mc, after Moscow and element 117, Tennessine, symbol Ts, after Tennessee.
      ::来自俄罗斯和美国的一组科学家 命名为元素115 莫斯科的莫斯科 符号Mc 和元素117 Tennessine 符号Ts 田纳西的田纳西
    • The Russian team that discovered element 118 named it Oganesson, symbol Og, after Yuri Oganessian, a prolific element hunter.
      ::发现第118号元素的俄罗斯小组 命名为Oganesson Ognesson, 符号Og, 以尤里·奥加尼西亚命名, 是一个巨大的元素猎人。

    Q: Find calcium (Ca) in the Figure . How many energy levels have electrons in them for atoms of calcium?
    ::Q: 在图中查找钙 (Ca) 。其中有多少原子的钙的电能水平?

    A: Calcium is in period 4, so its atoms have electrons in them for the first four energy levels.
    ::A:钙在4期,因此其原子在前4年的能量水平上含有电子。

    Groups of the Modern Periodic Table
    ::现代定期表格各群体

    Columns of the modern table are called groups , as they are in Mendeleev’s table. However, the modern table has many more groups—18 compared with just 8 in Mendeleev’s table. Elements in the same group have similar properties. For example, all elements in group 18 are colorless, odorless , such as neon (Ne). (Neon is the element inside the light in opening photo C.) In contrast, all elements in group 1 are very reactive solids. They react explosively with water, as you can see in the video and Figure .
    ::现代表格的列称为群,如门捷列夫的表。然而,现代表格的组数更多,为18个,而门捷列夫的表数只有8个。同一组的元素具有相似的特性。例如,18组的所有元素无色、无味,如Neon(Ne)等。 (Neon是开张照片C中的光线内元素。 )相比之下,第1组的所有元素都是非常有反应性的固体。它们与水发生爆炸性反应,正如您在视频和图中看到的。

    Sodium reacting with water, producing a large explosion and bright colors.

    The alkali metal sodium (Na) reacting with water.
    ::碱金属钠(Na)与水发生反应。

    Classes of Elements
    ::要件类别

    All elements can be classified in one of three classes: , , or . Elements in each class share certain basic properties. For example, elements in the metals class can conduct electricity, whereas elements in the nonmetals class generally cannot. Elements in the metalloids class fall in between the metals and nonmetals in their properties. An example of a metalloid is arsenic (As). (Arsenic is the element in opening photo B.) In the periodic table above, elements are color coded to show their class. As you move from left to right across each period of the table, the elements change from metals to metalloids to nonmetals.
    ::所有元素都可以分为三种类别之一: , 或 。 每个类别中的元素具有某些基本特性。 例如, 金属类中的元素可以进行电力操作, 而非金属类中的元素一般不能进行电力操作。 金属类中的元素在其特性中在金属和非金属之间发生作用。 一种甲类的示例是砷( As )。 ( 张开照片 B. 中的元素是 。 ) 在以上定期表格中, 元素有颜色编码以显示其类别。 在表格的每个时期从左向右移动时, 元素从金属向甲类向非金属变化。

    Q: To which class of elements does copper (Cu) belong: metal , metalloid, or nonmetal? Identify three other elements in this class.
    ::问题:铜(Cu)属于哪一类元素:金属、金属类、金属类或非金属类?确定本类中的其他三个元素。

    A: In the Figure , the cell for copper is colored blue. This means that copper belongs to the metals class. Other elements in the metals class include iron (Fe), sodium (Na), and gold (Au). It is apparent from the table that the majority of elements are metals.
    ::A:在图A中,铜的电池是蓝色的,这意味着铜属于金属类,金属类中的其他元素包括铁(Fe)、钠(Na)和黄金(Au)。从表中可以明显看出,大部分元素是金属。

    Summary
    ::摘要

    • The modern periodic table is used to organize all the known elements. Elements are arranged in the table by increasing atomic number.
      ::现代周期表用于组织所有已知元素,各元素按增加原子数排列。
    • In the modern periodic table, each element is represented by its chemical symbol. The number above each symbol is its atomic number. Atomic numbers increase from left to right and from top to bottom in the table.
      ::在现代周期表中,每个元素的化学符号代表每个元素。每个符号上方的数字是原子数。原子数在表格中从左到右和从上到下都有增加。
    • Rows of the periodic table are called periods. From left to right across a period, each element has one more proton than the element before it.
      ::周期表格的行被称为时间段。从左到右跨时间段,每个元素的质子比其面前的元素多一个。
    • Columns of the periodic table are called groups. Elements in the same group have similar properties.
      ::周期表中的列被称为组。同一组的元素具有相似的属性。
    • All elements can be classified in one of three classes: metals, metalloids, or nonmetals. Elements in each class share certain basic properties. From left to right across each period of the periodic table, elements change from metals to metalloids to nonmetals.
      ::所有元素都可分为三类之一:金属、金属类、金属类或非金属类。每类元素具有某些基本特性。从左到右,在周期表的每个周期,元素从金属到金属类变成非金属类。

    Review
    ::回顾

    1. What is the modern periodic table?
      ::现代周期表是什么?
    2. Compare and contrast the periods and groups of the modern periodic table.
      ::比较和比较现代周期表格的时期和组别。
    3. In the modern periodic table shown in Figure 1  , find the element named lead (Pb). How many protons do atoms of lead have? To which class of elements does lead belong?
      ::在图1所示现代周期表中,找到名为铅(Pb)的元素。有多少质子的铅原子存在?铅属于哪一类元素?
    4. Which groups of the modern periodic table contain elements that are classified as metalloids?
      ::现代周期表中哪几组含有被归类为类体元素的元素?