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  • 电云原子模型

    A fan turned off on the left and running at high speed on the right.

    The fan pictured here is turned off in the photo on the left and running at high in the photo on the right. In the right-hand photo, the blades are moving too fast for you to see the individual blades. You can’t tell where any given blade is at any given moment. In some ways, rapidly moving fan blades are similar to electrons moving about the nucleus of an . Like fan blades, electrons move very quickly and we can never tell exactly where they are. If that’s the case, how can we represent electrons in models of the atom?
    ::这里所拍摄的风扇在左边的照片中被关闭,在右边的照片中高处运行。在右手照片中,刀片移动太快,你看不到个别的刀片。你无法在任何特定时刻辨别给定的刀片在哪里。在某些方面,迅速移动的扇片片与围绕一个原子核移动的电子类似。像扇片片一样,电子移动非常迅速,我们永远无法知道它们的确切位置。如果是这样的话,我们如何在原子模型中代表电子呢?

    Where Are the Electrons?
    ::电子人在哪里?

    Up until about 1920, scientists accepted Niels Bohr’s model of the atom. In this model, negative electrons circle the positive nucleus at fixed distances from the nucleus, called levels. You can see the model in Figure for an atom of the nitrogen. Bohr’s model is useful for understanding properties of elements and their chemical interactions. However, it doesn’t explain certain behaviors of electrons, except for those in the simplest atom, the hydrogen atom.
    ::直到1920年左右,科学家接受了尼尔斯·伯赫尔的原子模型。 在这个模型中,负电子将正核旋转在与核的固定距离上,也就是所谓的水平。 你可以在图中看到氮原子的模型。 布尔的模型有助于理解元素的特性及其化学相互作用。 但是,它并没有解释电子的某些行为,除了最简单的原子,即氢原子。

    Nitrogen atom with nucleus and surrounding electrons illustrating the electron cloud model.

    What Are the Chances?
    ::什么是机会?

    In the mid-1920s, an Austrian scientist named Erwin Schrödinger thought that the problem with Bohr’s model was restricting the electrons to specific orbits. He wondered if electrons might behave like light, which scientists already knew had properties of both particles and waves. Schrödinger speculated that electrons might also travel in waves. 
    ::20世纪20年代中期,奥地利科学家Erwin Schrödinger(Erwin Schrödinger)认为博尔模型的问题在于将电子限制在特定的轨道上。 他想知道电子行为是否像光一样,而科学家已经知道光是粒子和波的特性。 Schrödinger推测电子也可能在波浪中流动。

    Q: How do you pin down the location of an in a wave?
    ::问题:你如何确定波浪的位置?

    A: You can’t specify the exact location of an electron. However, Schrödinger showed that you can at least determine where an electron is most likely to be.
    ::A: 您无法指定电子的确切位置 。 然而, Schrödinger 显示您至少可以确定电子最有可能在哪里 。

    Schrödinger developed an equation that could be used to calculate the chances of an electron being in any given place around the nucleus. Based on his calculations, he identified regions around the nucleus where electrons are most likely to be. He called these regions orbitals . As you can see in the Figure , orbitals may be shaped like spheres, dumbbells, or rings. In each case, the is at the center of the orbital. 
    ::Schrödinger开发了一个方程式,可用于计算在核心周围任何特定位置的电子存在的可能性。根据他的计算,他确定了核心周围最有可能有电子的区域。他将这些区域称为轨道区域。从图中可以看出,轨道的形状可能像球体、哑铃或环。在每种情况下,轨道都位于轨道的中心。

    Representations of atomic orbitals: s, p, and d shapes showing electron distribution around the nucleus.

    A Fuzzy Cloud
    ::模糊的云

    Schrödinger’s work on orbitals is the basis of the modern model of the atom, which scientists call the quantum mechanical model. The modern model is also commonly called the electron cloud model. That’s because each orbital around the nucleus of the atom resembles a fuzzy cloud around the nucleus, like the ones shown in the Figure for a helium atom. The densest area of the cloud is where the electrons have the greatest chances of being.
    ::Schrödinger在轨道上的工作是现代原子模型的基础,科学家称之为量子机械模型。 现代模型也通常被称为电子云模型。 这是因为原子核心周围的每个轨道都像核周围的模糊云层,就像图中显示的原子。 云中最稠密的地区是电子最有可能存在的地区。

    Representation of a helium atom's electron cloud surrounding the nucleus.

    Q: In the model pictured in the Figure , where are the two helium electrons most likely to be?
    ::问题:在图中描绘的模型中,最有可能找到的两枚氦电子在哪里?

    A: The two electrons are most likely to be inside the sphere closest to the nucleus where the cloud is darkest.
    ::A:两种电子最有可能存在于最接近云层最暗的核心的球体内。

    Summary
    ::摘要

    • Bohr’s model of the atom, in which electrons circle the nucleus at fixed energy levels, cannot explain all the behaviors of electrons.
      ::Bohr的原子模型是电子在固定能量水平上圆圆核,无法解释电子的所有行为。
    • In the 1920s, Erwin Schrödinger proposed that electrons travel in waves, which means their exact positions cannot be determined. He developed an equation to calculate the chances of an electron being in any given place. Using his equation, he identified regions around the nucleus, called orbitals, where electrons are most likely to be.
      ::在1920年代,Erwin Schrödinger建议电子在波浪中流动,这意味着其确切位置无法确定。他开发了一个方程式来计算电子在任何特定地点存在的可能性。他用方程式确定了核心周围的区域,叫做轨道,那里最有可能有电子。
    • Orbitals are the basis of the electron cloud model of the atom. This model is still accepted by scientists today.
      ::轨道是原子电子云模型的基础,目前科学家仍然接受这一模型。

    Review
    ::回顾

    1. What is the problem with Bohr’s model of the atom?
      ::Bohr的原子模型有什么问题?
    2. How did Schrödinger resolve this problem?
      ::Schrödinger是如何解决这个问题的?
    3. Describe orbitals.
      ::描述轨道。
    4. Outline the electron cloud model of the atom.
      ::外观原子的电子云模型 。

    Explore More
    ::探索更多

    Watch the video about the electron cloud model below, and then answer the questions that follow.
    ::观看下面电子云模型的视频, 然后回答接下来的问题。

     

     

     

     

     

    1. What influences the movement of electrons in atoms?
      ::原子中电子的移动会受到什么影响?
    2. What is the Heisenberg uncertainty principle?
      ::海森堡不确定原则是什么?
    3. How is the Heisenberg uncertainty principle related to electron orbitals?
      ::海森堡不确定性原则如何与电子轨道轨道相关?

    Resources
    ::资源