The Electron Configuration Calculator is a powerful chemistry tool that determines the electron arrangement of an atom or ion based on its atomic number. Instead of manually filling orbitals using complex quantum rules, this calculator instantly generates accurate electron configurations in standard notation.
It helps students, teachers, and professionals quickly understand how electrons are distributed across energy levels and subshells.
This calculator is based on atomic structure and quantum mechanics principles, specifically:
Aufbau Principle
– Electrons fill the lowest energy orbitals first
Pauli Exclusion Principle
– Each orbital holds a maximum of two electrons with opposite spins
Hund’s Rule
– Electrons fill empty orbitals singly before pairing
These rules determine how electrons occupy atomic orbitals.
Electron configuration follows the orbital filling sequence:
Orbital Filling Order:
1s → 2s → 2p → 3s → 3p → 4s → 3d → 4p → 5s → 4d → 5p → 6s → 4f → 5d → 6p → 7s
Maximum electrons per subshell:
s = 2 electrons
p = 6 electrons
d = 10 electrons
f = 14 electrons
These principles guide how electrons are distributed in atoms.Problem: Find the electron configuration of Iron (Fe), atomic number 26.
Step 1: Start filling orbitals in order
1s² → 2s² → 2p⁶ → 3s² → 3p⁶ → 4s²
Electrons used so far = 20
Step 2: Continue filling
Remaining electrons = 6
Next subshell = 3d
Step 3: Complete configuration
Final Answer:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶
Shorthand form: [Ar] 4s² 3d⁶