Section outline

  • Variety of screws in different sizes and shapes next to a coin for scale.

    Can you guess what types of metals these screws are made of?
    ::你能猜出这些螺丝是由什么类型的金属制成的吗?

    Screws come in all sizes and shapes.  They are all (well, almost all) made of some kind of metal .  But they have differences in size, shape, and type of metal.  Physical characteristics also differ.  Some screws are long, and others are short.  One screw may have a flat-head slot while another screw may have a Phillips-head.  Some of the screws in the picture below are used to fasten things together, and others are used to hang heavy objects on a wall.
    ::螺丝有各种大小和形状。 螺丝都是某种金属的( 几乎全部) 。 但金属的大小、 形状和类型各有不同 。 物理特性也各有不同 。 有些螺丝长, 另一些则短。 一个螺丝可能有一个平头孔, 而另一个螺丝可能有一个菲利普头。 下面的螺丝有些用来把东西固定在一起, 另一些螺丝则用来把重物挂在墙上 。

    Chemists classify materials in many ways.  We can sort on the basis of their arrangements. The way the electrons are distributed determines the chemical properties of the element. Another way is to classify elements based on . Some common physical properties are color, volume , and density.  Other properties that allow us to sort on the basis of behavior are conduction of and electricity, malleability (the ability to be hammered into very thin sheets), ductility (the ability to be pulled into then wires), melting point , and boiling point . Three broad classes of elements based on physical properties are metals, , and .
    ::化学家以多种方式对材料进行分类。 我们可以根据它们的安排进行分类。 电子的分布方式决定元素的化学特性。 另一种方法是根据元素进行分类。 一些共同的物理特性是颜色、 体积和密度。 使我们能够根据行为进行分类的其他特性包括导电、 易变能力( 被敲成非常薄的薄片的能力)、 粘附能力( 被拉入电线的能力)、 熔点和沸点。 基于物理特性的三大元素类别是金属、 和 。

    Metals
    ::金属

    A metal is an element that is a good conductor of heat and electricity. Metals are also malleable, which means that they can be hammered into very thin sheets without breaking. They are ductile, which means that they can be drawn into wires. When a fresh surface of any metal is exposed, it will be very shiny because it reflects light well. This is called luster. All metals are solid at room temperature with the exception of mercury (Hg), which is a . Melting points of metals display a very wide variance. The melting point of mercury is -39°C, while the highest melting metal is tungsten (W), with a melting point of 3422°C. The elements in blue in the periodic table below are metals.  About 80 percent of the elements are metals.
    ::金属是一种良好的热电导体。 金属也是可移动的, 也就是说, 金属可以不折不扣地被压成非常薄的薄板。 金属是粘土, 也就是说, 金属可以被扯入电线中。 当任何金属的新鲜表面暴露时, 它会非常闪亮, 因为它能反映光亮。 这叫做光亮。 所有金属在室内温度下都是固态的, 但汞(Hg)除外。 金属的熔点显示出非常大的差异。 汞的熔点是- 39°C, 而最高的熔融金属是tungsten(W), 熔点为3422°C。 下面周期表中的蓝色元素是金属。 大约80%的元素是金属。

    Periodic table with elements highlighted in blue representing metals.

    Gold has been used by many civilizations for making jewelry (see Figure ).  This metal is soft and easily shaped into a variety of items.  Since gold is very valuable and often used as currency, gold jewelry has also often represented wealth.
    ::许多文明利用黄金制作首饰(见图 ) 。 这种金属软软,很容易形成各种物品。 由于黄金非常宝贵,经常被用作货币,黄金首饰也常常代表财富。

    Several gold rings and a gold necklace displayed on a surface.
    Gold jewelry.

    Copper is a good conductor of electricity and is very flexible and ductile.  This metal is widely used to conduct electric current in a variety of appliances, from lamps to stereo systems to complex electronic devices (see Figure ).
    ::铜是良好的电力导体,非常灵活和诱导,这种金属广泛用于在各种电器中进行电流,从灯泡到立体系统到复杂的电子装置(见图[...])。

    Exposed copper wire showing strands; demonstrates copper's conductive properties.
    Copper wire exposed.

    Mercury is the only metal to exist as a liquid at room temperature (see Figure ).  This metal was extensively used in thermometers for decades until information about its toxicity became known.  Mercury switches were once common, but are no longer used.  However, new federally-mandated energy-efficient light bulbs that are now used contain trace amounts of mercury and represent a hazardous waste.
    ::汞是唯一在室温下作为液体存在的金属(见图 ):该金属在温度计中被广泛使用达数十年之久,直到了解其毒性信息为止;汞开关曾经是常见的,但已不再使用;不过,目前使用的联邦授权的新的节能灯泡含有微量汞,是一种危险废物。

    Liquid mercury being poured into a petri dish, illustrating its unique physical properties.
    Pouring Mercury.

     

     

     

    Summary
    ::摘要

    • Metals are good conductors of heat and electricity.
      ::金属是热电的良好导体。
    • Metals are malleable and ductile
      ::金属是易流和诱导的金属
    • All metals are solids at room temperature with the exception of mercury
      ::除汞外,所有金属都是室温下的固体,只有汞除外。
    • Gold, silver, iron, and mercury are typical metals.
      ::黄金、银、铁和汞是典型的金属。

    Review
    ::回顾

    1. What properties of an element are affected by electron distribution?
      ::电子分布对某一元素的什么特性产生影响?
    2. Define malleability.
      ::定义易行性。
    3. Define ductility.
      ::定义管道。
    4. State one reason gold is used in jewelry.
      ::国家的一个原因是珠宝用黄金。
    5. Why is mercury no longer used in many devices?
      ::为什么汞不再用于许多设备?