2.1.3 Ground State Atoms (or Molecules) and Excited Atoms

(or Molecules)The atom is primary particle which cannot be divided in a chemical reaction,but itcan be divided in the physical state. The atom consists of a nucleus and anextranuclear part,so it is a nuclear structure. The atom is the smallest unit of ane ......（本文共 9078 字 ）     [阅读本文] >>