I want to point out that the zero energy is defined as when you have a naked proton -- where the electron has popped out -- that's what we've defined as zero energy up to this point when we're talking about single atoms.

我想指出，这里零点能的定义,是当我们只有一个裸露的质子,而没有电子时-,到目前为止对零点能一直采用这样的定义,当我们在讨论单个原子时。

麻省理工公开课 - 化学原理课程节选

So that's going to be the end of the exam 1 material, and then we'll move on to exam 2 material, which is kind of exciting, because we've been talking about just individual atoms and ions up to this point, and now we can talk about molecules, so we're going to start talking about bonding.

到此为止就是第一次考试的内容，接下来我们会开始讲第二次考试的内容，这些内容令人有点兴奋，因为我们一直都只是在讨论单个的原子,和离子到目前为止，而现在我们可以讨论分子了，要开始讨论成键的问题了。

麻省理工公开课 - 化学原理课程节选