：On a submicroscopic level, there is no boundary strict between particles and wave.
→When existence is regarded as a wave motion, in physics, it is called a "place." For example, light is wave motion of an electric field and magnetic field.
※ The electron is wave.
※ And the length of orbit around the nucleus is an integer multiple of the wavelength (10 minus 10 square m).
※ It is impossible to determine the size of the electron.
※ It is under a very microscopic situation like an electron beam that the character as a wave is actually observed.