If you see a problem that asks you, for example, the third ionization energy versus taking a second electron out of the 2 s in a photoelectron spectroscopy experiment, those are two very different things.

如果你遇到一个题目问你的是，比如说，是第三电离能,还是在光电子能谱实验中从，2，s，轨道中,拿走第二个电子，这可是两个完全不同的问题。

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