Electron Configuration Calculator
Find the complete electron configuration, noble gas notation, valence electrons, and electron shell distribution for any element from the periodic table.
Enter element symbol (e.g., Fe, Au, O) or atomic number (e.g., 26)
What is electron configuration?
Electron configuration describes the arrangement of electrons in an atom's orbitals. It follows the Aufbau principle, filling orbitals from lowest to highest energy: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p. Each orbital can hold up to 2 electrons with opposite spins.
How do you write electron configuration?
Write electron configuration by filling orbitals in order of increasing energy. For example, carbon (6 electrons): 1s² 2s² 2p². Use superscripts to show electrons in each orbital. For orbitals with multiple electrons (p, d, f), distribute electrons one by one before pairing (Hund's rule).
What are valence electrons?
Valence electrons are electrons in the outermost shell (highest principal quantum number n). They determine chemical behavior and bonding. For main group elements: valence electrons = electrons in s and p orbitals of highest n. For transition metals: typically electrons in (n-1)d and ns. Example: Na has 1 valence electron (3s¹); Fe has 2 valence electrons (4s²).
What is the noble gas shorthand?
Noble gas shorthand uses the previous noble gas in brackets to simplify configurations. Instead of writing all inner electrons, use [Ar] for Argon (1s² to 3p⁶). Example: Potassium (Z=19) = [Ar]4s¹ instead of 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹. This makes longer configurations much simpler.