The most popular picture is that of a tiny solar system, with the atomic nucleus as a solid, planet-like sphere orbited by one or more electrons in a series of concentric rings. The image is simplistic, and wrong. Others scientists explain that the laws of nature which exist at the infinitesimal size of atomic particles simply are different from the laws that govern airplanes, trees, baseballs, and water puddles.
Electrons are are neither particles nor waves alone, but both at the same time.
Subatomic particles even react differently to energy. Add a little energy to a proton, and nothing happens. Like that string, a proton or neutron can exist only at certain energy levels, and at no others. Physicists know that it is impossible to add energy continuously to a subatomic particle. But if a particle is hit with enough energy in one burst, it will transition into a higher energy state.