English: Atomic hydrogen-like single-electron orbital showing ${\displaystyle \psi _{n{=}4,l{=}0,m{=}0}}$, also called 4s-orbital. The image is a 3D rendering of the spatial density distribution of |𝜓|² with the color depicting the phase of 𝜓. The spatial distribution is smooth and vanishes for large radii. The cloud is a more realistic representation of an orbital than the more common solid-body approximations. At full resolution, 1Å=6.3px.