4.18 同位素同位素

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  同位素同位素同位素

  

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  Are all the members of the football team shown above identical? 
  ::足球队所有队员是否都显示相同?

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  They are on the same team and are all known by the same team name, but there are individual differences among the players.  We do not expect the kicker to be as big as the quarterback.  The tight end is very likely to weigh less than the defensive tackle on the other side of the ball.  They play as a unit, but they have different weights and heights.
  ::他们都是同一组人,他们都以同一组人的名字而为人所知,但参赛者之间有个别的差别。 我们不期望踢球的大小会像四分卫一样大。 紧尾的重量可能比球另一侧的防守杆要轻。 他们作为一个队来玩,但他们有不同的重量和高度。

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  Isotopes
  ::离线( I)

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  The history of the is full of some of these differences.  Although John Dalton stated in his atomic theory of 1804 that all atoms of an are identical, the discovery of the began to show that this assumption was not correct. The study of radioactive materials  (elements that spontaneously give off particles to form new elements) by Frederick Soddy (1877-1956) gave important clues about the internal structure of atoms.  His work showed that some substances with different radioactive properties and different atomic  masses were in fact the same element.  He coined the term isotope from the Greek roots isos (íσος “equal”) and topos (τóπος “place”). He described isotopes as, “Put colloquially, their atoms have identical outsides but different insides.” Soddy won the Nobel Prize in Chemistry in 1921 for his work.
  ::尽管约翰·道尔顿在其1804年的原子理论中指出,所有原子都是相同的,但发现这些原子开始表明这一假设是不正确的。弗雷德里克·索迪(1877-1956年)对放射性材料(自发释放粒子以形成新元素的元素)的研究(1877-1956年)为原子内部结构提供了重要线索。他的工作表明,某些具有不同放射性特性的物质和不同的原子群其实是相同的元素。他从希腊根部(“平等 ” 和“地方 ” 中创建了同位素术语 。 他将同位素描述为 , “ 交替地说,它们的原子外部是相同的,内部是不同的 ” 。 Soddy在1921年赢得了诺贝尔化学奖。

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  As stated earlier, not all atoms of a given element are identical. Specifically, the number of neutrons can be variable for many elements. As an example, naturally occurring carbon exists in three forms. Each carbon atom has the same number of (6), which is its . Each carbon atom also contains six electrons in order to maintain electrical neutrality. However the number of neutrons varies as six, seven, or eight. Isotopes are atoms that have the same number atomic number, but different mass numbers due to a change in the number of neutrons.
  ::如前所述,并非某一元素的所有原子都是相同的。 具体地说, 中子的数量可以在许多元素中变化。 例如, 自然产生的碳以三种形式存在。 每个碳原子的编号为(6), 即它的编号。 每个碳原子也包含六种电子, 以保持电子中性。 然而, 中子的数量是6、 7 或 8 。 Isotops 是具有相同原子数的原子, 但是由于中子数量的变化, 不同的质量数量 。

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  The three isotopes of carbon can be referred to as carbon-12 $\begin{align*}\left(^{12}_{6}\text{C}\right)\end{align*}$ , carbon-13 $\begin{align*}\left(^{13}_{6}\text{C}\right)\end{align*}$ , and carbon-14 $\begin{align*}\left(^{14}_{6}\text{C}\right)\end{align*}$ refers to the nucleus of a given isotope of an element. A carbon atom is one of three different nuclides . Most elements naturally consist of mixtures of isotopes. Carbon has three natural isotopes, while some heavier elements can have many more. Tin has ten stable isotopes, the most of any element.
  ::碳的三种同位素可称为碳-12(612C)、碳-13(613C)和碳-14(614C),指某一元素的某一同位素核。碳原子是三种不同的核素之一。大部分元素自然由同位素混合物组成。碳有三种天然同位素,而一些较重元素可以有更多的。锡有十种稳定的同位素,大多数元素。

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  While the presence of isotopes affects the mass of an atom, it does not affect its chemical reactivity. Chemical behavior is governed by the number of electrons and the number of protons. Carbon-13 behaves chemically in exactly the same way as the more plentiful carbon-12.
  ::虽然同位素的存在会影响原子的质量,但它不会影响原子的化学反应。化学行为受电子数量和质子数量的制约。碳-13的化学行为方式与碳-12的化学行为方式完全相同。

     

   

   

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  Summary
  ::摘要

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  • Isotopes are atoms that have the same atomic number, but different mass numbers due to a change in the number of neutrons.
    ::Isotopotos是原子,原子数相同,但由于中子数量的变化,质量数字不同。
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  • The term nuclide refers to the nucleus of a given isotope of an element.
    ::核素一词指元素的某一同位素核。
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  • The atomic mass of an atom equals the sum of the protons and the neutrons.
    ::原子原子质量等于质子和中子的总和。

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  Review
  ::回顾

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  1. What are isotopes?
     ::什么是同位素?
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  2. Why do different isotopes of an element generally have the same physical and chemical properties?
     ::为什么元素的不同同位素通常具有相同的物理和化学特性?
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  3. How would the nucleus of the hydrogen-1 and hydrogen-2 differ?
     ::氢一核与氢二核有何不同?
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  4. Relate the concepts of isotope and mass number.
     ::将同位素和质量编号的概念联系起来。
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  5. All oxygen atoms have eight protons, and most have eight neutrons as well.  What is the mass number of an oxygen isotope that has nine neutrons?  What is the name of this isotope?
     ::所有氧原子都有8个质子,大多数也有8个中子。一个含9个中子的氧同位素的质量数量是多少?这个同位素叫什么名字?
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  6. An isotope of yttrium has 39 protons and 59 neutrons. What is the mass number of that isotope?
     ::yttrium同位素有39个质子和59个中子。该同位素的质量数量是多少?
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  7. An isotope with a mass number of 193 has 116 neutrons. What is the atomic number of this isotope?
     ::质量数为193的同位素有116个中子。这种同位素的原子数是多少?
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  8. An isotope of barium (atomic number 56) has an mass of 138. How many neutrons are in the nucleus of this isotope?
     ::同位素(原子编号56)质量为138,有多少中子在同位素核中?

  Relate the concepts of isotope and mass number.