The smallest particles of the world are not even invisible to the naked eye, but the most modern microscopes cannot detect them. We can know by our chemical knowledge, that there are atoms which can be detected by electro microscope. But how big are these atoms? An atom's diameter is about 10?10 meter. A mole contains 6x1023 peace of atoms. We could picture it as if an atom's amplitude was a grain of dust, a mole atom would be a size of a Himalaya mountain. An atom consists of electron shells and the atomic nucleus. In the electron shells circle negligible scale, but big charge negative electrons, and the atomic nucleus consist of nucleons (protons and neutrons), which give the mass of the atom. The protons have as big charge as the electrons, just they have positive charge. Thus the atom is neutral. This picture demonstrates very well the buildup of the atom: