题目

已知锰的核电荷数为25，以下是一些同学绘制的基态锰原子核外电子的轨道表示式（即电子排布图），其中最能准确表示基态锰原子核外电子运动状态的是 A．       B．  C． D． 答案：D    －What do you think of chemistry? －In my opinion, chemistry is ________ physics． [　　] A．subject so difficult as B．as difficult a subject as C．as a difficult subject as D．difficult as a subject as