The electron configurations of elements 1 through 120 are displayed in a dash-and-arrow chart. You can move the slider to select an atomic number to see the corresponding element name and electron configuration. Also shown is a simple spherical model to represent the comparative size of the atom. The reference sphere has a radius of 248, one unit higher than the largest atomic radius, that of praseodymium. Covalent radius data is used when available; otherwise, a calculated value is used. When no data is available, only a static sphere appears.