This series of lines makes up the chemical element's spectrum, which differs from that of any other element. Quantum mechanics shows that electrons and other atomic particles of matter are also associated with waves. These waves, called matter waves, have a specific wavelength. The wavelength is inversely proportional to the particle's momentum. The particle's momentum is calculated by multiplying the mass of the particle by its velocity.
Matter waves provide an explanation for the arrangement of electrons in separate orbits.
When an electron is undisturbed, its wave fits around the atom's nucleus at a distance such that the wave can join smoothly onto itself. The electrons of a single atom have waves of different wavelengths. These electrons form orbits at varying distances from the nucleus. Another fundamental idea of quantum mechanics is the uncertainty principle. According to this principle, the position and velocity of a particle cannot simultaneously be measured with exactness.