Electron Configuration — Explained
Electron configuration describes how electrons are distributed across the orbitals of an atom. It’s essential for predicting chemical behavior: bonding patterns, magnetism, and ionization properties. This calculator helps you get both the full configuration and the noble‑gas shorthand for any neutral atom.
Why it matters
Knowing the electron configuration lets chemists and students predict the valence electrons, oxidation states, and the element’s placement in the periodic table. For example, the configuration of iron (Fe) is [Ar] 4s2 3d6, which indicates 6 d‑electrons and 2 s‑electrons in the outer shells.
Examples
- Hydrogen (H): 1s1
- Carbon (C): 1s2 2s2 2p2
- Chromium (Cr): [Ar] 3d5 4s1 (anomalous configuration)
Common questions
Q: What is noble‑gas shorthand?A: It uses the previous noble gas in brackets to replace the inner core electrons. Example: sodium is [Ne] 3s1.Q: Does this calculator handle ions?A: Currently it computes neutral atoms. If you need ionic configurations, enter the total electron count (atomic number ± charge) using the “Total electrons” box.Q: Why are some electron configurations “anomalous”?A: Certain elements gain extra stability from half‑filled or fully filled d and f subshells. The calculator accounts for the most common exceptions.
Further reading
Electron Configuration Calculator
Determine the distribution of electrons in atomic orbitals for any element
Select an Element
Common Elements
Electron Configuration
Orbital Filling Diagram
Step-by-Step Process
Aufbau Principle – Orbital Filling Order
Memory Aid:
1s → 2s → 2p → 3s → 3p → 4s → 3d → 4p → 5s → 4d → 5p → 6s → 4f → 5d → 6p → 7s → 5f → 6d → 7p
“Smart Physicists Can Find Gold Particles”
Electron Configuration Rules
- Aufbau Principle: Electrons fill orbitals from lowest to highest energy
- Pauli Exclusion Principle: Each orbital holds max 2 electrons with opposite spins
- Hund’s Rule: Electrons fill degenerate orbitals singly before pairing up
Orbital Capacities
- s orbitals: 1 orbital × 2 electrons = 2 electrons
- p orbitals: 3 orbitals × 2 electrons = 6 electrons
- d orbitals: 5 orbitals × 2 electrons = 10 electrons
- f orbitals: 7 orbitals × 2 electrons = 14 electrons
Notation Guide
- 1s²: Principal quantum number (1), orbital type (s), electron count (2)
- [He]: Noble gas core notation for 1s²
- ↑↓: Paired electrons in an orbital
- ↑ : Unpaired electron in an orbital
Common Electron Configurations
Hydrogen (H) – 1 electron
Simplest configuration with one electron in 1s orbital
Carbon (C) – 6 electrons
Hund’s rule: two unpaired electrons in 2p orbitals
Neon (Ne) – 10 electrons
Noble gas with completely filled first and second shells
Copper (Cu) – 29 electrons
Exception: half-filled/filled d-subshell stability
Electron Configuration — Explained
Electron configuration describes how electrons are distributed across the orbitals of an atom. It’s essential for predicting chemical behavior: bonding patterns, magnetism, and ionization properties. This calculator helps you get both the full configuration and the noble‑gas shorthand for any neutral atom.
Why it matters
Knowing the electron configuration lets chemists and students predict the valence electrons, oxidation states, and the element’s placement in the periodic table. For example, the configuration of iron (Fe) is [Ar] 4s2 3d6, which indicates 6 d‑electrons and 2 s‑electrons in the outer shells.
Examples
- Hydrogen (H): 1s1
- Carbon (C): 1s2 2s2 2p2
- Chromium (Cr): [Ar] 3d5 4s1 (anomalous configuration)
Common questions
Q: What is noble‑gas shorthand?A: It uses the previous noble gas in brackets to replace the inner core electrons. Example: sodium is [Ne] 3s1.Q: Does this calculator handle ions?A: Currently it computes neutral atoms. If you need ionic configurations, enter the total electron count (atomic number ± charge) using the “Total electrons” box.Q: Why are some electron configurations “anomalous”?A: Certain elements gain extra stability from half‑filled or fully filled d and f subshells. The calculator accounts for the most common exceptions.
Further reading
Learn about Hund’s rule, Pauli exclusion principle, and aufbau principle to deepen your understanding of how orbitals are filled.
Learn about Hund’s rule, Pauli exclusion principle, and aufbau principle to deepen your understanding of how orbitals are filled.
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