带负电的物体有将多余电子向中性物体上转移的倾向，而带正电的材料有从中性物体上吸收电子的倾向。

Negatively charged objects try to give up their excess electrons to neutral bodies, while positively charged materials try to extract electrons from neutral bodies.

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The reason is because we already have a full valence shell for our hydrogen, it doesn't want any more electrons.

原因是因为我们的氢,已经有一个排满的价壳层了，它不再需要多余的电子了。

麻省理工公开课 - 化学原理课程节选

we start high and go low, we're dealing with emission where we have excess energy that the electron's giving off, and that energy is going to be equal the energy of the photon that is released and, of course, through our equations we know how to get from energy to frequency or to wavelength of the photon.

当我们从高到低时，我们说的,是发射,电子有多余的能量给出，这个能量等于，发出,光子的能量，当然我们可以通过方程,从能量知道，光子的频率，和波长。

麻省理工公开课 - 化学原理课程节选