Electron Configuration Calculator - Determine Electron Configuration of Atoms
Electron configuration is the arrangement of electrons in atomic orbitals. Electron filling follows the Aufbau principle (electrons fill lower energy orbitals first), Hund's rule (electrons fill orbitals with parallel spins first), and the Pauli exclusion principle (maximum 2 electrons per orbital with opposite spins). The orbital filling order follows the Moeller diagram: 1s → 2s → 2p → 3s → 3p → 4s → 3d → 4p → 5s → 4d → 5p → 6s → 4f → 5d → 6p... Each s orbital holds a maximum of 2 electrons, p holds 6, d holds 10, and f holds 14 electrons.
Order: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶...Variables:
- nPrincipal quantum number(e.g.: 1, 2, 3...)
- lAzimuthal quantum number(e.g.: s(0), p(1), d(2), f(3))
- ZAtomic number(e.g.: 26 (Fe))
Categories:
How to Use the Calculator
- 1
Enter Atomic Number
Enter the element's atomic number (Z = number of electrons).
- 2
Calculate
Click calculate to get the electron configuration.
- 3
View Result
See the full electron configuration for that element.
Examples
Iron (Fe)
Determine the electron configuration of Iron with atomic number 26.
- 1.Z = 26 → 26 electrons
- 2.Order: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶
- 3.Total: 2+2+6+2+6+2+6 = 26 ✓
Iron has 2 valence electrons in 4s and 6 electrons in 3d.
Oxygen (O)
Determine the electron configuration of Oxygen (Z=8).
- 1.Z = 8 → 8 electrons
- 2.Order: 1s² 2s² 2p⁴
- 3.Total: 2+2+4 = 8 ✓
Oxygen has 6 valence electrons (2s² 2p⁴).