Section outline

  • Radioactive decay, showing nucleus emitting radiation and a particle.

    This diagram could almost illustrate a pinball game. It actually illustrates the process of . This is a process that occurs all around you. It may even occur inside your body.
    ::此图表几乎可以说明弹球游戏。 它实际上可以说明 。 这是一个在你周围发生的过程, 甚至可能发生在你的身体里 。

    Q: Based on the diagram, what happens during radioactive decay?
    ::问题:根据图表,在放射性衰变期间会发生什么?

    A: The nucleus of a radioactive gives off radiation in the form of and a particle of matter.
    ::A:放射性核以物质的形式和粒子释放出辐射。

    Introducing Radioactive Decay
    ::引入放射性衰减

    Radioactive decay is the process in which the nuclei of radioactive atoms emit charged particles and energy, which are called by the general term radiation . Radioactive atoms have unstable nuclei, and when the nuclei emit radiation, they become more stable. Radioactive decay is a nuclear—rather than chemical—reaction because it involves only the nuclei of atoms. In a nuclear reaction, one may change into another. 
    ::放射性衰变是放射性原子核心释放有电粒子和能量的过程,一般术语称之为辐射,放射性原子有不稳定的核,当核放射辐射时,放射性原子就更加稳定。放射性衰变是一种核反应,而不是化学反应,因为它只涉及原子核心。在核反应中,人们可能会变成另一种。

     

     

     

     

     

     

    Types of Radioactive Decay
    ::放射性衰减类型

    There are several types of radioactive decay, including alpha, beta, and . In all three types, nuclei emit radiation, but the nature of the radiation differs. The Table shows the radiation emitted in each type of decay. 
    ::放射性衰变有几种类型,包括甲型、乙型和。在所有三种类型中,核都释放辐射,但辐射的性质有所不同。表显示了每种类型的衰变所排放的辐射。

    Type Radiation Emitted
    alpha particle (2 and 2 neutrons) + energy
    beta particle (1 electron) + energy
    Gamma decay energy (gamma ray)

    It’s Elemental
    ::它是元素

    Both alpha and beta decay change the number of protons in an atom’s nucleus, thereby changing the atom to a different element. In alpha decay, the nucleus loses two protons. In beta decay, the nucleus either loses a proton or gains a proton. In gamma decay, no change in proton number occurs, so the atom does not become a different element.
    ::阿尔法和贝塔的衰变都会改变原子核中的质子数量,从而将原子改变为不同的元素。 在阿尔法衰变中,核会失去两个质子。 在乙型衰变中,核要么失去质子,要么获得质子。 在伽玛的衰变中,质子数量不会发生变化,因此原子不会成为不同的元素。

    Q: If the radioactive element polonium (Po) undergoes alpha decay, what element does it become?
    ::问题:如果放射性元素(Po)发生α衰变,它会变成什么元素?

    A: From the periodic table , the of polonium is 84, so it has 84 protons. If it loses two protons through alpha decay, it will have 82 protons. Atoms with 82 protons are the element lead (Pb).
    ::A:从周期表中,为84个,因此它有84个质子。如果它通过阿尔法衰减而失去两个质子,它就有82个质子。元素铅(Pb)是原子,其中82个质子是原子,其中82个质子是原子。

    Dangers of Radioactive Decay
    ::放射性衰减的危险

    The charged particles and energy emitted during radioactive decay can harm living things, but the three types of radioactive decay aren’t equally dangerous. That’s because they differ in how far they can travel and what they can penetrate. You can see this in the Figure .
    ::放射性衰变期间释放的带电粒子和能量会危害生命,但三种类型的放射性衰变并不同样危险。 这是因为它们能行进到多远和能穿透多少不同。 你可以从图中看到这一点。

    Comparison of alpha, beta, and gamma radiation penetration through paper, aluminum, and lead.

    Alpha particles can travel only a few centimeters through air. They can burn the skin but not penetrate it. Beta particles can travel up to a meter through air. They can penetrate and damage skin. Gamma rays can travel thousands of meters through air. They can penetrate and damage cells deep inside the body.
    ::Alpha 粒子只能在空气中穿行几厘米。 它们可以烧灼皮肤, 但不穿透皮肤。 Beta 粒子可以穿透到一米, 可以穿透和损害皮肤。 Gamma 射线可以通过空气穿透数千米。 它们可以穿透和破坏身体深处的细胞。

    Summary
    ::摘要

    • Radioactive decay is the process in which unstable nuclei of radioactive atoms become stable by emitting charged particles and energy.
      ::放射性衰变是放射性原子的不稳定核心通过排放有电粒子和能量而变得稳定的过程。
    • There are three types of radioactive decay: alpha decay, beta decay, and gamma decay. Alpha and beta decay change one element into another. Gamma decay does not.
      ::放射性衰变有三种类型:α衰变、β衰变和伽马衰变。阿尔法和β衰变将一个元素变成另一个元素。伽玛衰变不会。
    • Radioactive decay can damage living things. Alpha decay is the least damaging, and gamma decay is the most damaging.
      ::放射性衰变会损害生命。 阿尔法衰变是破坏最小的,伽玛衰变是破坏最大的。

    Review
    ::回顾

    1. What is radioactive decay?
      ::什么是放射性衰变?
    2. Compare and contrast alpha, beta, and gamma decay.
      ::对比和对比阿尔法,贝塔, 和伽马腐烂。