This page is designed to allow you to manipulate images of atomic orbitals and compare multiple orbitals (up to four) by displaying them simultaneously on one atom. The goal is to help you visualize atomic orbitals and their relative sizes.

You will notice that these orbitals look somewhat different from the orbitals on a one electron hydrogen atom. Generally, orbitals in many electron atoms appear to be somewhat more squat than the equivalent hydrogen atom orbitals. As the nuclear charge increases orbitals also get more compact. This is expected because of the increased electrostatic attraction between the nucleus and each electron.

Below (you may need to scroll down) is a box with a small sphere in it. The sphere represents the location of a krypton nucleus (significantly enlarged so that you can see it). To the right (or below on a narrow screen) are dropdown selectors from which you can choose an orbital to display and control the appearance of each orbital. The orbitals appear in the dropdowns in the order orbitals are filled when assigning configurations using the periodic table: lowest energy (at top) to highest energy (at bottom).

The electronic configuration of a ground state krypton is [Ar]4s²3d¹⁰4p⁶ , in compact notation simply [Kr] or in fully expanded notation 1s²2s² 2p⁶3s²3p⁶4s²3d¹⁰4p⁶. This means that all the shells with electrons in them are fully occupied. Thus, the actual order of orbital energies in the Kr atom (lowest to highest) is: 1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p. Notice this is not the filling order from the periodic table, where the 4s fills before the 3d. Once you reach neutral atoms where the 3d sub-shell is full, the 4s subshell is higher energy than the 3d sub-shell.