6.22 定期趋势:金属和非金属特性
章节大纲
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What are we eating as a nation?
::我们作为一个民族在吃什么?The graph above indicates some trends in the U.S. diet over a thirty-year period. By observing the direction our eating habits are going, we can take steps to help prevent bad eating habits and decrease problems such as high blood pressure and heart attacks.
::上图显示了三十年来美国饮食的某些趋势。 通过观察饮食习惯的方向,我们可以采取措施帮助防止不良饮食习惯,减少高血压和心脏病发作等问题。Development of the periodic table has helped organize chemical information in many ways. We can now see trends among properties of different atoms and make predictions about the behavior of specific materials.
::定期表格的发展有助于以多种方式组织化学信息,我们现在可以看到不同原子特性的趋势,并对特定材料的行为作出预测。Metallic and Non-metallic Character
::金属和非金属特性Metallic character refers to the level of reactivity of a metal . tend to lose electrons in , as indicated by their low ionization energies . Within a , metal atoms have relatively low attraction for electrons, as indicated by their low electronegativities. By following the trend summary in the figure below, you can see that the most reactive metals would reside in the lower left portion of the periodic table. The most reactive metal is cesium, which is not found in nature as a free . It reacts explosively with water and will ignite spontaneously in air. Francium is below cesium in the alkali metal group, but is so rare that most of its properties have never been observed.
::金属特性指金属的反活动水平。 其电离性能低表明, 金属往往会失去电子。 在金属原子中,金属原子对电子的吸引力相对较低, 其电子强度较低。 根据下图中的趋势摘要, 你可以看到, 最有反应力的金属将居住在周期表的左下角。 最有反应力的金属是, 它在性质上不是免费的。 它与水发生爆炸性反应, 会在空气中自燃。 在碱金属组中, 低于, 但非常罕见, 其特性大部分从未被观察到 。Trends in behaviors of elements.
::元素行为的趋势。Reactivity of metals is based on processes such as the formation of halide compounds with and how easily they displace hydrogen from dilute acids.
::金属的抗反应基于过程,例如卤化物化合物与稀释酸的形成,以及它们如何容易将氢从稀释酸中去除。The metallic character increases as you go down a group. Since the ionization energy decreases going down a group (or increases going up a group), the increased ability for metals lower in a group to lose electrons makes them more reactive. In addition, the atomic radius increases going down a group, placing the outer electrons further away from the nucleus and making that less attracted by the nucleus.
::金属字符随着一个组的下降而增加。由于电离化能量减少一个组(或增加一个组的上升),一个组中较低金属失去电子的能力增加,使得它们更具反应性。此外,原子半径增加一个组,将外部电子离核更远地置于核之外,使核心吸引较少。tend to gain electrons in chemical reactions and have a high attraction for electrons within a compound. The most reactive nonmetals reside in the upper right portion of the periodic table. Since the are a special group because of their lack of reactivity, the element fluorine is the most reactive nonmetal. It is not found in nature as a free element. Fluorine reacts explosively with many other elements and compounds and is considered to be one of the most dangerous known substances .
::最反应性的非金属存在于周期表的右上角。由于该物质缺乏反应性,因此属于特殊群体,因此元素氟是反应性最大的非金属。在性质上,该元素不是自由元素。氟与许多其他元素和化合物发生爆炸性反应,被认为是已知的最危险物质之一。Note that there is no clear division between metallic and non-metallic character. As we move across the periodic table, there is an increasing tendency to accept electrons (non-metallic) and a decrease in the possibility that an would give up one or more electrons.
::请注意,金属特性和非金属特性之间没有明确的区分。 随着我们跨过周期表,人们越来越倾向于接受电子(非金属),而放弃一种或多种电子的可能性也越来越小。Summary
::摘要-
Metallic character refers to the level of reactivity of a metal.
::金属特性指金属的回反应水平。 -
Non-metallic character relates to the tendency to accept electrons during chemical reactions.
::非金属特性与在化学反应期间接受电子的趋势有关。 -
Metallic tendency increases going down a group.
::金属趋势会增加 向下下降一个群体。 -
Non-metallic tendency increases going from left to right across the periodic table.
::非金属趋势在周期表中从左向右上升。
Review
::回顾-
Define “metallic character.”
::“金属特性”的定义。 -
Define “non-metallic character.”
::“非金属特性”的定义。 -
Describe the trend in metallic character going down a group.
::描述金属特性向下下降的一组趋势。 -
Describe the trend in non-metallic character going across the periodic table.
::说明周期表中的非金属特性趋势。 -
Why does the metallic character increase as you go down a group?
::为什么金属性格会随着你组群的下降而增加?
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Metallic character refers to the level of reactivity of a metal.
