Section outline

  • General

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  • 定期趋势:碘化能源

    • Define ionization .
      ::定义电离化。
    • Describe factors affecting ionization .
      ::说明影响电离化的因素。
    • Describe how ionization energy changes across a period.
      ::说明电离化能源在一段时间内是如何变化的。
    • Describe how ionization energy changes down a group.
      ::描述电离化能源如何向下向一组变换。

    Aerial view of a flock of sheep grazing near a winding river in a field.

    Why do sheep travel in herds?
    ::为什么绵羊在牧群中旅行?

    Like many other , sheep travel in herds.  The tendency is for each individual sheep to stay with the herd. However, a sheep may sometimes wander off, depending on how strong the attraction is for a particular food or supply.  At other times, a sheep may become frightened and run off.  Whether a sheep chooses to stay with the herd or go its own way depends on the balance between attraction to the herd and attraction to the outside influence.
    ::与许多其他羊群一样,绵羊以畜群方式旅行,趋势是羊与牛群同住,但羊有时会闲逛,取决于对特定食物或供应的吸引力有多大,有时绵羊可能害怕和逃跑,羊是否选择与牛群同住或自己走自己的路取决于对牛群的吸引力与对外部影响的吸引力之间的平衡。

    There is an on-going tension between the electrons and in an .  Reactivity of the depends in part on how easily the electrons can be removed from the atom.  We can measure this quantity and use it to make predictions about the behaviors of atoms.
    ::电子与一个原子之间存在持续紧张。 电子的反作用部分取决于电子从原子中移走的方便程度。 我们可以测量这个数量, 并用它来预测原子的行为 。

    Ionization Energy

    ::碘化能源

    Ionization energy is the energy required to remove an from a specific . It is measured in kJ/mol, which is an energy unit, much like calories. The ionization energies associated with some are described in  Table . For any given atom, the outermost will have lower ionization energies than the inner-shell kernel electrons. As more electrons are added around a , the outer electrons become shielded from the nucleus by the inner shell electrons. This is called shielding .
    ::离子化能量是去除特定电源所需的能量。它用KJ/mol测量,这是一个能量单位,与热量非常相似。与某些电离化能量相关的电离能量在表表 中描述。对于任何给定原子,外层的电离能量将比内壳内核电子低。随着在外壳周围添加更多的电子,外层电子被内壳电子遮蔽在核之外。这被称为屏蔽。

    Ionization Energies (kJ/mol) of the First 18 Elements

    Element
    ::要素要素

    IE 1

    ::IE1

    IE 2
    ::IE2

    IE 3
    ::IE3

    IE 4
    ::IE4

    IE 5
    ::IE5

    IE 6
    ::IE6

    H
    ::赫 时

    1312

     

     

    		     

    He
    ::他,他,他,他,

    2373

    5251

     

     

     

     

    Li
    ::李李

    520

    7300

    11,815

     

     

     

    Be
    ::贝贝

    899

    1757

    14,850

    21,005

     

     

    B
    ::BB ,B

    801

    2430

    3660

    25,000

    32,820

     

    C
    ::C 中 C

    1086

    2350

    4620

    6220

    38,000

    47,261

    N
    ::N 内

    1400

    2860

    4580

    7500

    9400

    53,000

    O
    ::OO

    1314

    3390

    5300

    7470

    11,000

    13,000

    If we plot the first ionization energies vs. for the main group elements, we would have the following trend
    ::如果我们为主要组群元素绘制第一种电离化能量相对于主要组元素的图,我们就会有以下趋势:

    Graph showing the trend of ionization energy versus atomic number for main group elements.
    Ionization energy and atomic number.

    Moving from left to right across the periodic table , the ionization energy for an atom increases.  We can explain this by considering the nuclear charge of the atom.  The more protons in the , the stronger the attraction of the nucleus to electrons.  This stronger attraction makes it more difficult to remove electrons. 
    ::从左向右跨过周期表,原子的电离化能量增加。 我们可以从原子的核电量来解释这一点。 质子越多,核心对电子的吸引力就越强。 这种更强的吸引力使得清除电子更加困难。

    Within a group, the ionization energy decreases as the size of the atom gets larger.  On the graph, we see that the ionization energy increases as we go up the group to smaller atoms.  In this situation, the first removed is farther from the nucleus as the atomic number (number of protons) increases.  Being farther away from the positive attraction makes it easier for that electron to be pulled off.
    ::在一个组内, 离子化能量随着原子大小的增大而减少。 在图形中, 我们看到离子化能量随着我们组升到小原子组而增加。 在这种情况下, 随着原子数量( 质子数量) 的增加, 第一个离核更远。 离正吸引距离越远, 电子就更容易被拉离 。

    Graph showing trends of ionization energy, electron affinity, atomic radius, and character in the periodic table.

     

     

    Summary

    ::摘要

    • Ionization energy refers to the amount of energy needed to remove an electron from an atom.
      ::电离化能量是指从原子中去除电子所需的能量量。
    • Ionization energy decreases as we go down a group.
      ::离子化能量减少 当我们下降一个组。
    • Ionization energy increases from left to right across the periodic table.
      ::在周期表中从左到右增加电离电能。

    Review
    ::回顾

    1. Define “ionization energy.”
      ::“电离化能源”的定义。
    2. Do valence electrons have larger or smaller ionization energies than the inner-shell kernel electrons?
      ::等值电子的电离化能量是否大于或小于内壳内核电子?
    3. What is electron shielding?
      ::什么是电子屏蔽?
    4. Describe the trends in ionization energy from left to right across the periodic table.
      ::横跨周期表格,说明从左到右的电离化能源趋势。
    5. Describe the trends in ionization energy from top to bottom of a group in the periodic table.
      ::说明定期表中一组人从上到下电离化能源的趋势。
    6. Why is the second ionization energy for lithium so much larger than the first ionization energy?
      ::为什么锂的第二个离子化能源比第一个离子化能源大得多?
    • electron shielding: As more electrons are added to a nucleus, the outer electrons become shielded from the nucleus by the inner shell electrons
      ::电子屏蔽:随着更多的电子被添加到核中,外部电子被内壳电子遮蔽在核中
    • ionization energy: The energy required to remove an electron from a specific atom. It is measured in kJ/mol, which is an energy unit, much like calories.
      ::电离化能量:从特定原子中去除电子所需的能量。用KJ/mol测量,这是一个能量单位,类似于卡路里。