Electron Configuration of Argon (Ar)
What is the electron configuration of Argon?
The electron configuration of Argon (Ar, Z=18) is 1s² 2s² 2p⁶ 3s² 3p⁶. In noble gas shorthand: [Ne] 3s² 3p⁶. It has 0 unpaired electron(s) and is a p-block element.
| Symbol | Ar |
| Atomic Number | 18 |
| Full Electron Configuration | 1s² 2s² 2p⁶ 3s² 3p⁶ |
| Noble Gas Shorthand | [Ne] 3s² 3p⁶ |
| Block | p |
| Period | 3 |
| Group | 18 |
| Unpaired Electrons | 0 |
| Exception? | No |
Orbital Filling Order
Following the aufbau principle, the 18 electrons in Argon fill orbitals in order of increasing energy: 1s (2 electrons), then 2s (2 electrons), then 2p (6 electrons), then 3s (2 electrons), then 3p (6 electrons).
Each orbital is filled according to the Pauli exclusion principle (at most 2 electrons per orbital) and Hund's rule (electrons occupy degenerate orbitals singly before pairing).
Noble Gas Shorthand
The inner electrons of Argon match the configuration of Ne. This allows us to abbreviate the configuration as [Ne] 3s² 3p⁶, where [Ne] represents the filled core and the remaining entries show the valence electrons.
Valence Electrons
The valence shell of Argon contains 2 electrons in the 3s subshell and 6 electrons in the 3p subshell. These outermost electrons determine Argon's chemical reactivity, bonding behavior, and position in the periodic table as a p-block element in period 3.
Visualize orbital filling with 3D orbital shapes, aufbau principle, and noble gas shorthand for 36 elements.
Explore Argon in the Electron Configuration ExplorerRelated Topics
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Electron Configuration of Carbon
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Electron Configuration of Neon
Orbital filling for Neon (p-block)
Argon on the Periodic Table
Full properties and periodic trends for Argon
Orbital Hybridization
See how atomic orbitals mix to form sp, sp2, and sp3 hybrids