上物理课了啊：每个原子有三部分组成质子、中子和电子，质子带正电荷，电子带负电荷，中子不带电荷；质子和中子包裹在原子核里。质子和中子装在原子核里，而电子在外面绕着旋转。质子的数量决定一个原子的化学特性~~~
❤《万物简史》推出部落节目版，戳这里订阅:http://bulo.hujiang.com/menu/6004/

文中需听写单词或词组用[-No-]表示，句子用[---No---]表示。请边听写边理解文意，这样可以提高听力准确度，并为训练听译打下基础哦~~~
Let us pause for a moment and consider the structure of the atom as we know it now. Every atom [-1-] three kinds of elementary particles: protons, which have a positive electrical charge; electrons, which have a negative electrical charge; and neutrons, which have no charge. Protons and neutrons [-2-] the nucleus, while electrons spin around outside. [---3---] An atom with one proton is an atom of hydrogen, one with two protons is helium, with three protons is lithium, [-4-] . Each time you add a proton you get a new element. ([---5---], you will sometimes see it written that it is the number of electrons that defines an element; it comes to the same thing. [---6---])
Neutrons don't influence an atom's identity, but they do add to its mass. [---7---] Add a neutron or two and you get an isotope. The terms you hear [-8-] dating techniques in archeology refer to isotopes--carbon-14, for instance, which is an atom of carbon with six protons and eight neutrons ([-9-]).
is made from are packed into The number of protons is what gives an atom its chemical identity. and so on up the scale Because the number of protons in an atom is always balanced by an equal number of electrons The way it was explained to me is that protons give an atom its identity, electrons its personality. The number of neutrons is generally about the same as the number of protons, but they can vary up and down slightly. in reference to the 14 being the sum of the two
让我们稍停片刻，先来考虑一下现在我们所知道的原子结构。每个原子都由三种基本粒子组成：带正电荷的质子，带负电荷的电子，以及不带电荷的中子。质子和中子装在原子核里，而电子在外面绕着旋转。质子的数量决定一个原子的化学特性。有一个质子的原子是氢原子；有两个质子的原子是氦原子；有三个质子的原子是锂原子；如此往上增加。你每增加一个质子就得到一种新元素。（由于原子里的质子数量总是与同样数量的电子保持平衡，因此你有时候会发现有的书里以电子的数量来界定一种元素，结果完全一样。有人是这样向我解释的：质子决定一个原子的身份，电子决定一个原子的性情。） 中子不影响原子的身份，但却增加了它的质量。一般来说，中子数量与质子数量大致相等，但也可以稍稍多一点或少一点。增加或减少一两个中子，你就得到了同位素。考古学里就是用同位素来确定年代的--比如，碳－14是由6个质子和8个中子组成的碳原子（因为二者之和是14）。