Electron Configuration Calculator
By Atomic Number
Common Elements
Formula
Aufbau order: 1s → 2s → 2p → 3s → 3p → 4s → 3d → 4p → 5s → 4d → 5p → ...
Frequently Asked Questions
What is electron configuration?
Electron configuration describes how electrons are distributed among the atomic orbitals of an atom. It follows the Aufbau principle (fill lowest energy first), Pauli exclusion principle (max 2 electrons per orbital), and Hund's rule (fill orbitals singly first).
Why are Cr and Cu exceptions?
Chromium (Z=24) has [Ar]4s¹3d⁵ instead of [Ar]4s²3d⁴, and copper (Z=29) has [Ar]4s¹3d¹⁰ instead of [Ar]4s²3d⁹. Half-filled (d⁵) and fully filled (d¹⁰) d subshells have extra stability due to exchange energy.
You may also need
A
Bond Order Calculator
Free bond order calculator. Calculate bond order from molecular orbital theory (bonding and antibonding electrons) or look up common diatomic molecules.
ScienceA
Molecular Geometry (VSEPR) Calculator
Free VSEPR molecular geometry calculator. Determine molecular shape, bond angles, hybridization, and polarity from bonding and lone pairs using VSEPR theory.
Science