Does anyone have that in their brain somewhere for ready use? I don't, in fact, so it's actually okay if you don't know all your common ions, if you missed that part.

你们有谁有印象它们有什么用吗？,我当时是不知道，所以如果你们不记得,这部分也没有关系。

麻省理工公开课 - 化学原理课程节选