章节大纲

  • 常规

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  • 原子与分子

    Close-up view of patterned structures, illustrating the concept of small particles in matter.
     

    Can you see matter?
    ::你能看到东西吗?

    Matter is all around you. Everything you see is matter. All of this matter is made of small particles. The small particles are made of smaller particles.
    ::物质环绕着你。 你看到的一切都是物质。 所有物质都是由小粒子组成的。小粒子是由小粒子组成的。

    What is Matter?
    ::什么是物质?

    To understand  , we must first understand matter.  Matter  is the substance that physical objects are made of.
    ::要理解,我们必须首先理解物质。物质是物理物体的物质。

    Atoms and Elements
    ::原子和元素

    The basic unit of matter is an  atom  ( Figure  ). At the center of an atom is its  nucleus .  Protons  are positively charged particles in the nucleus. Also in the nucleus are  neutrons  with no electrical charge. Orbiting the nucleus are tiny electrons.  Electrons  are negatively charged. An atom with the same number of protons and electrons is electrically neutral. If the atom has more or less electrons to protons it is called an  ion . An ion will have positive charge if it has more protons than electrons. It will have negative charge if it has more electrons than protons.
    ::基本物质单位是原子( 图表 ) 。 在原子的中心是其核。 质子是其核核中的正电荷颗粒。 质子是核中的正电荷颗粒。 核中也有无电荷的中子。 轨道核心是小电子。 电荷是负电荷。 质子和电子数量相同的原子是中性的。 如果原子对质子拥有或少于电子的电荷, 则称为离子。 离子如果其质子比电子多, 则具有正电荷。 如果它拥有比质子更多的电子, 则具有负电荷。

    An illustration of an atom showing nucleus with protons and neutrons, and orbiting electrons.
     
    The nucleus of an atom is made up of protons (blue) and neutrons (yellow). Electrons (red) orbit around the nucleus.

    An atom is the smallest unit of a chemical  element . That is, an atom has all the properties of that element. All atoms of the same element have the same number of protons.
    ::原子是化学元素中最小的单位。也就是说,原子具有该元素的所有特性。同一元素的所有原子都有相同数量的质子。

     

     

    Molecules and Compounds
    ::分子和化合物

    A  molecule  is the smallest unit of a  chemical compound . A compound is a substance made of two or more elements. The elements in a chemical compound are always present in a certain ratio.
    ::分子是化学化合物中最小的单位,化合物是由两个或两个以上元素组成的物质,化学化合物中的元素总是以一定比例存在。

    Water  is probably one of the simplest compounds that you know. A water molecule is made of two hydrogen atoms and one oxygen atom ( Figure  ). All water molecules have the same ratio: two hydrogen ions to one oxygen ion.
    ::水可能是最简单的化合物之一。水分子由两个氢原子和一个氧原子组成(图)。所有水分子的比例相同:两个氢离子和一个氧离子。

    Representation of a water molecule with two gray hydrogen ions and one red oxygen ion.
     
    A water molecule has two hydrogen ions (shown in gray) bonded to one oxygen ion (shown in red).

    Summary
    ::摘要

    • An atom has negatively-charged electrons in orbit around its nucleus.
      ::原子核心周围的轨道上有负电荷电子。
    • The nucleus of an atom is composed of positively-charged protons, and neutrons, which have no charge.
      ::原子的核心由无电的正充电质子和中子组成。
    • An atom that gains or loses electrons is an ion.
      ::产生或失去电子的原子就是离子

    Review
    ::回顾

    1. Describe the parts of an atom. Where are these parts located?
      ::描述原子的部位。这些部位在哪里?
    1. What is an element?
      ::什么是要素?
    1. What is a molecule made of?
      ::分子是由什么制造的?
    1. How is an ion different from an atom?
      ::离子和原子有什么不同?