Electronic configuration of elements and ions
Atomic Structure · Chemistry
Molecule viewer
Interactive 3DBall-and-stick models with true bond angles — switch molecule to compare shapes.
Controls
Drag the sliders or type a value — the simulation updates live.
Study notes
Write configurations for Fe (Z=26) and Fe²⁺. Step 1: Fe: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶ = [Ar] 4s² 3d⁶. Step 2: For Fe²⁺, remove 2 electrons — from 4s FIRST (highest n). Step 3: Fe²⁺: [Ar] 3d⁶. (NOT [Ar] 4s² 3d⁴!) Step 4: Fe³⁺ would be [Ar] 3d⁵ — the stable half-filled d. Rule: fill by (n+l), but remove by highest n.
Related topics
- Dalton's atomic theory and its limitations
- Subatomic particles: discovery of electron, proton, neutron
- Atomic models: Thomson, Rutherford, Bohr
- Bohr model: energy levels, radius, hydrogen spectrum
- Rydberg formula and spectral series (Lyman, Balmer, Paschen, Brackett, Pfund)
- Wave–particle duality and de Broglie wavelength