Electron Configuration Calculator
Instantly find an element’s electron distribution, noble-gas shorthand, and valence electrons by selecting an element from the dropdown menu below.
Equation Preview
Helping Notes
Electrons fill orbitals from lower to higher energy; within a subshell, occupy singly before pairing.
Shorthand uses the previous noble gas in brackets, then the remaining subshells for the selected element.
Some elements promote an electron for stability (e.g., chromium, copper, silver, gold).
Results
Selected Element
Atomic Number
Full Electron Configuration
Noble-Gas Shorthand
Valence Electrons
What Is Electron Configuration Calculator?
The Electron Configuration Calculator is a dedicated tool that maps an element’s electrons into shells and subshells using well‑established quantum rules. It interprets the Aufbau principle, the Pauli exclusion rule, and Hund’s rule to produce compact notations such as 1s² 2s² 2p⁶ or noble‑gas shorthand like [Ar] 4s² 3d⁶. By entering an element name, symbol, atomic number, or an ionic charge, the calculator returns ground‑state configurations, highlights outer‑shell electrons, and clarifies valence patterns essential for bonding, periodic trends, and spectroscopy.
About the Electron Configuration Calculator
Designed for students, educators, and researchers, the Electron Configuration Calculator automates a task that is otherwise error‑prone when performed manually. It follows the energy ordering given by the n + ℓ rule, accounts for subshell capacities, and supports standard conventions, including noble‑gas cores for readability. The interface emphasizes clarity: results are presented in linear spectroscopic notation and in structured blocks so you can quickly identify valence electrons, partially filled subshells, and predicted magnetic behavior. Support for ions allows quick checks of oxidation states commonly encountered in coordination chemistry and materials science.
How to Use this Electron Configuration Calculator
1) Enter an element (e.g., Fe) or atomic number (e.g., 26). 2) Optionally add charge (e.g., 3+ or 2−). 3) Submit to generate the ground‑state configuration. 4) Use noble‑gas shorthand toggle to condense inner electrons. 5) Review the valence and electron count summary for reactivity insights. The calculator applies Aufbau filling, enforces two electrons per orbital with opposite spins, and distributes electrons among degenerate orbitals before pairing, reflecting Hund’s rule.
Examples Using the Electron Configuration Calculator
• Oxygen (O, Z = 8): 1s² 2s² 2p⁴ → oxide ion O2−: 1s² 2s² 2p⁶.
• Iron (Fe, Z = 26): [Ar] 4s² 3d⁶; Fe3+ commonly: [Ar] 3d⁵.
• Copper (Cu, Z = 29): [Ar] 4s¹ 3d¹⁰ (observed stability).
• Krypton (Kr, Z = 36): [Ar] 4s² 3d¹⁰ 4p⁶ (closed shell).
Core Formulas for Electron Placement
The following formulas guide shell capacities, subshell limits, and energy ordering. They are provided in inline data attributes so your page can render them responsively.
Maximum electrons in principal shell n.
Allowed electrons per subshell type.
Aufbau ordering via the n + ℓ rule.
Total electrons equals atomic number minus the ionic charge (use positive q for cations, negative for anions).
Distribution across equal‑energy orbitals.
FAQs
How is noble‑gas shorthand chosen?
The closest preceding noble gas (e.g., [Ar] for K–Ca–… series) replaces inner electrons to keep the configuration concise and readable.
How does the calculator treat ions?
It adjusts electron count using the charge, then removes or adds electrons following energy order; for transition metals, electrons are removed from the outer ns before (n−1)d.
Why does copper show [Ar] 4s¹ 3d¹⁰ instead of [Ar] 4s² 3d⁹?
Enhanced stability arises from a filled d subshell and reduced electron–electron repulsion, making the observed configuration energetically favorable.
Can I get valence electron counts from the result?
Yes. The outermost shell and partially filled subshells are summarized so you can infer valence electrons used in bonding and reactivity.
Does it handle excited states?
The default output is the ground state. Excited configurations are context‑dependent and typically require spectroscopic inputs not included in routine calculations.