Electron Configuration of Oxygen (O)
What is the electron configuration of Oxygen?
The electron configuration of Oxygen (O, Z=8) is 1s² 2s² 2p⁴. In noble gas shorthand: [He] 2s² 2p⁴. It has 2 unpaired electron(s) and is a p-block element.
| Symbol | O |
| Atomic Number | 8 |
| Full Electron Configuration | 1s² 2s² 2p⁴ |
| Noble Gas Shorthand | [He] 2s² 2p⁴ |
| Block | p |
| Period | 2 |
| Group | 16 |
| Unpaired Electrons | 2 |
| Exception? | No |
Orbital Filling Order
Following the aufbau principle, the 8 electrons in Oxygen fill orbitals in order of increasing energy: 1s (2 electrons), then 2s (2 electrons), then 2p (4 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 Oxygen match the configuration of He. This allows us to abbreviate the configuration as [He] 2s² 2p⁴, where [He] represents the filled core and the remaining entries show the valence electrons.
Valence Electrons
The valence shell of Oxygen contains 2 electrons in the 2s subshell and 4 electrons in the 2p subshell. These outermost electrons determine Oxygen's chemical reactivity, bonding behavior, and position in the periodic table as a p-block element in period 2.
Visualize orbital filling with 3D orbital shapes, aufbau principle, and noble gas shorthand for 36 elements.
Explore Oxygen in the Electron Configuration ExplorerRelated Topics
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Electron Configuration of Boron
Orbital filling for Boron (p-block)
Oxygen on the Periodic Table
Full properties and periodic trends for Oxygen
Orbital Hybridization
See how atomic orbitals mix to form sp, sp2, and sp3 hybrids