TABLE OF CONTENTS Everything starts with the atom, the building block of the nanoworld, and also of our world. Mass is predominantly concentrated in the nucleus of the atom, which is made up of particles called protons which have a positive electric charge, and of neutrons which are neutral, but which have the same mass as protons. The neutrons stabilize the confinement of the protons which are subject to their mutual electrostatic repulsion. This nucleus is packed with negatively charged particles called electrons which are equal in number to the number of protons. The atomic unit is therefore neutral. It is the distribution of electrons that is the origin of the atom s chemical properties.
The electron is a particle. It has a weak mass, almost 1/2,000of that of a proton, and it carries the basic electric charge that creates electricity. Like the proton, it has a magnetic field called spin that leads to magnetism which has multiple uses; we will see more of this later. But this is not all; the electron is also a wave, the frequency of which depends on its energy. Without it, the world would not exist. It is not enough to compare the image of small electrons orbiting around the nucleus to the planets orbiting around the sun, or to compare the electrostatic force of attraction in atoms to the force of gravitational attraction for the planets. It neither explains the stability of the system, for...
