A learning portal from FabLab Bergamo
Build its electron configuration. Rotate its orbitals. Explore how probability clouds turn into the structure of an element.
OBSERVE · COMPARE · UNDERSTAND
Place electrons one at a time. Read orbital boxes, compare shell totals, and see Aufbau, Hund’s rule and Pauli pairing in action. The filling lesson covers all 118 elements, including d and f subshells.
Open the filling animation →Open the viewer and choose hydrogen orbitals. Rotate the probability cloud to see lobes and nodes from different angles. Quantum numbers describe the state; the point cloud shows its spatial distribution.
Open the 3D viewer →In the viewer, choose Element Explorer. Compare elements and use shell dissection to inspect the occupied subshells. This wider atom model complements the introductory filling lesson.
Explore elements →| Term | Meaning | Electron capacity |
|---|---|---|
| Shell | A principal level identified by n, such as n = 2. | At most 2n² |
| Subshell | A family within a shell: s, p, d or f. | 2, 6, 10 or 14 |
| Orbital | One spatial state within a subshell; shown as one box. | At most 2, with opposite spins |
Shells do not simply fill one after another. For example, 4s begins before 3d. Use calcium to see the difference between a shell’s capacity and its actual occupancy.
For a deeper dive, follow the path from a wavefunction to a rotating probability cloud. These technical guides are in English.
How angular and radial functions become sampling distributions.
How orbital and atomic radial tables are prepared for the device.
How sampled coordinates become the points drawn on screen.
Explore screening, radial models and the structure of a complete atom.
No. Each dot is a sampled possible position. Together they show the spatial probability distribution, rather than a path around the nucleus.
They label electron spin states. Two arrows in the same box must have opposite directions; equal-energy orbitals fill singly before electrons pair.
Hydrogen uses the exact nonrelativistic solution. Helium through uranium use calculated LDA radial orbitals; heavier elements use a screened hydrogen-like approximation. Orbital sizes and nodes come from these models. Filling adds contributions from the final neutral atom, rather than recalculating an ion at every step.