电屏蔽

What is the goal of a roller derby game?
::滚轮游戏的目标是什么?

Roller derby is a popular sport, although it is unfamiliar to many people.  The basic purpose is to set one team member (the “jammer”) past the opposing team to score points.  Other members of the team serve as blockers to prevent the opposing team from stopping the jammer.  Blockers interfere with the interaction between the jammer and the opponents by getting between the jammer and the skaters trying to stop her.
::Roller derby是一项受欢迎的运动,虽然许多人对此并不熟悉。 基本目的是让一名队员(“Jammer ” ) 通过对阵队得分。 球队的其他成员充当阻塞员,阻止对阵队阻止干扰器。 阻塞员通过干扰器和滑冰者试图阻止她,干扰干扰器和对手之间的互动。

The attraction between an and the nucleus of the is not a simple issue.  Only with hydrogen is there a one-to-one relationship that can be discussed in terms of direct charge attraction.  As the size of the atom increases, the number of and electrons also increase. These changes influence how the nucleus attracts electrons.
::原子与核心之间的吸引力并不是一个简单的问题。 只有氢才有一对一的关系,可以用直接电荷的吸引力来讨论。随着原子的大小的增加,电子的数量和数量也随之增加。这些变化影响到核心是如何吸引电子的。

Electron Shielding
::电屏蔽

In general, the ionization energy of an atom will increase as we move from left to right across the periodic table . There are several exceptions to the general increase in ionization energy across a period. The of Group 13 (B, Al, etc.) have lower ionization energies than the elements of Group 2 (Be, Mg, etc.). This is an illustration of a concept called “ electron shielding .” Outer electrons are partially shielded from the attractive force of the protons in the nucleus by inner electrons.
::一般说来,随着我们从左向右移动,原子的电离化能量会随着周期表的周期性向右移动而增加。在一段时间内,电离化能量普遍增加有几个例外。13组(B、Al等)的电离化能量低于2组(Be、Mg等)的能量。这说明了一个称为“电子屏蔽”的概念。外部电子被内部电子部分遮蔽,不受核心质子的吸引力。

To explain how shielding works, consider a lithium atom. It has three protons and three electrons – two in the first principal energy level and its in the second. The valence electron is partially shielded from the attractive force of the nucleus by the two inner electrons. Removing that valence electron becomes easier because of the shielding effect.
::为了解释屏蔽是如何起作用的,请考虑一个锂原子。它有三个质子和三个电子 — — 两个在第一个主要能源水平上,两个在第二个主要能源水平上。 valence 电子被两个内部电子部分地遮蔽在核心的吸引力之外。 去除valence 电子因为屏蔽效应而变得更加容易。

There is also a shielding effect that occurs between sublevels within the same principal energy level. Specifically, an electron in the “ s ” sublevel is capable of shielding electrons in the “ p ” sublevel of the same principal energy level. This is because of the spherical shape of the “ s ” . The reverse is not true – electrons in “ p ” orbitals do not shield electrons in “ s ” orbitals.
::同一主要能源水平内的子层之间也会产生一种屏蔽效应。 具体地说,“s”子层中的电子能够保护同一主要能源水平的“p”子层中的电子。 这是因为“s”的球形。 反之亦然 — — “p”轨道中的电子不能保护“s”轨道中的电子。

The electron being removed from an Al atom is a 3 p electron, which is shielded by the two 3 s electrons as well as all the inner core electrons . The electron being removed from a Mg atom is a 3 s electron, which is only shielded by the inner core electrons. Since there is a greater degree of electron shielding in the Al atom, it is slightly easier to remove the valence electron and its ionization energy is less than that of Mg. This is despite the fact that the nucleus of the Al atom contains one more proton than the nucleus of the Mg atom .
::从 Al 原子中移除的电子是一种3p 电子,由两个 3 电子和所有核心电子加以保护。从 Mg 原子中移除的电子是一种 3s 电子,仅由 内核心电子加以保护。由于 Al 原子中电子屏蔽程度较高,去除valance 电子的难度略小于 Mg 。尽管Al 原子核中所含质子比 Mg 原子核多一个质子,但事实并非如此。

There is another anomaly between Groups 15 and 16. Atoms of Group 16 (O, S, etc.) have lower ionization energies than atoms of Group 15 (N, P, etc.). Hund’s rule is behind the explanation. In a nitrogen atom, there are three electrons in the 2 p sublevel and each is unpaired. In an oxygen atom, there are four electrons in the 2 p sublevel, so one orbital contains a pair of electrons. It is that second electron in the orbital that is removed in the ionization of an oxygen atom. Since electrons repel each other, it is slightly easier to remove the electron from the paired set in the oxygen atom than it is to remove an unpaired electron from the nitrogen atom.
::第15组和第16组之间还有另一个异常点。 第16组(O、S等)的原子的电离能量比第15组(N、P等)的原子低。 解释的背后是Hund的规则。 在氮原子中,2p子层有3个电子,每个在2p子层没有孔。在氧原子中,有4个电子在2p子层,因此一个轨道上含有一对电子。在氧原子的电离中,轨道上的第二电子在氧原子的电离中被移除。由于电子相互反射,将电从氧原子中配对的电除去比从氮原子中去除一个无孔的电要容易得多。

Summary

::摘要

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• Electron shielding refers to the blocking of valence shell electron attraction by the nucleus due to the presence of inner-shell electrons.
  ::电屏蔽是指由于内壳电子的存在,核心对价值值贝壳电子吸引的屏蔽。
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• Electrons in an s orbital can shield p electrons at the same energy level because of the spherical shape of the s orbital.
  ::由于轨道的球状形状,轨道中的电子能够在相同的能量水平上保护p电子。
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• Electrons in paired spin configurations are slightly easier to remove than unpaired electrons.
  ::配对旋转配置中的电子比未受保护的电子更容易去除。

Review
::回顾

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1. Define “electron shielding."
   ::“电子屏蔽”的定义是“电子屏蔽”。
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2. Why do group 13 elements have lower ionization energies than group 2 elements?
   ::为什么第13组元素的电离化能量比第2组元素低?
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3. What influence does a larger shielding effect have on ionization energy?
   ::更大的屏蔽效应对电离化能源有什么影响?
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4. How do s orbit electrons affect the ionization energy of a p electron in the same shell?
   ::轨道电子如何影响同一罐壳中的小电子的电离能?
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5. Why do group 16 atoms have lower ionization energies than the corresponding group 15 atoms?
   ::为什么16个原子组的电离化能量比相应的15个原子组低?