Element identity
Atomic number, symbol, relative atomic mass display and periodic position are established reference data.
Atomic / electronic model
Ground-state electron configuration and atomic reference values are compiled/evaluated data; orbital graphics are teaching probability models, not photographs.
Material / molecular structure
The displayed ordinary structure is based on established material or molecular science; simplified viewers are labelled as teaching schematics where exact crystallographic coordinates are not rendered.
Temperature / phase path
Transition values are reference/evaluated values for the stated teaching path; pressure, purity and allotropy can matter.
Geography
Real pins use reviewed place/dataset context. Conceptual layers are used when country pins would imply false occurrence, unsafe inventory or an incomplete global distribution.
The lens describes evidence status, not confidence theatre. “Unknown” is kept unknown, and teaching schematics are not presented as direct measurements.
Oxygen (O)
Explore oxygen as an atom, the O₂ molecule, a powerful oxidizing partner, a major Earth-system element and a classic quantum-mechanics lesson: ordinary ground-state O₂ is paramagnetic because two electrons remain unpaired.
Oxygen atomic number, mass, protons, electrons and valence electrons
Oxygen: quick answers
How many protons, neutrons and electrons does oxygen have?
Oxygen’s atomic number is 8, so every oxygen atom has 8 protons, and a neutral atom also has 8 electrons. Its most common natural isotope, oxygen-16, has 8 neutrons (other isotopes have different neutron counts).
What is the symbol for oxygen?
The chemical symbol for oxygen is O.
Is oxygen a solid, liquid or gas at room temperature?
Oxygen is a gas at room temperature (about 25 °C).
What family (group) is oxygen in?
Oxygen is a nonmetal, in group 16, period 2 of the periodic table.
How many valence electrons does oxygen have?
Oxygen has 6 valence electrons, the electrons in its outer shell, which matches its position in group 16.
What is the electron configuration of oxygen?
The ground-state electron configuration of oxygen is [He] 2s² 2p⁴.
From atomic number to chemistry
Read these as a chain of causes, not as isolated facts. Each step links to the concept hub if you want the underlying idea explained.
Eight protons define oxygen; a neutral atom contains eight electrons.
Six valence electrons shape oxygen bonding and redox behavior.
Oxygen is a compact, highly electronegative chalcogen.
Molecular-orbital occupancy explains the paramagnetism of ordinary triplet O₂.
Oxygen sits in Group 16 with six valence electrons
Oxygen lies in Period 2 between nitrogen and fluorine. Six valence electrons, small atomic size and high electronegativity make oxygen a strong bonding partner across molecular, ionic and solid-state chemistry.
Oxygen Visual Lab
Decode the oxygen tile, rotate an ¹⁶O teaching model, inspect occupied atomic orbitals, build the O₂ magnetic story, then connect oxygen chemistry to air, water, steelmaking, medicine and combustion.
Seven facts packed into one square
Oxygen in one minute
Atomic number 8. Every oxygen nucleus contains eight protons.
Six valence electrons. [He] 2s² 2p⁴ is the neutral ground-state configuration.
O₂ is paramagnetic. Two unpaired electrons survive in the molecular-orbital ground state.
−2 is common, not universal. Peroxides and other species show why oxidation-state rules need context.
Oxygen is an Earth-system element. It is distributed through atmosphere, water, rocks and living systems.
2 · 6 electrons
Oxygen often forms two covalent bonds or gains electron density in oxide chemistry. High electronegativity helps make oxygen a strong partner in polar bonds and oxidation reactions.
At ordinary conditions elemental oxygen is molecular O₂ rather than a room-temperature crystal. The two bond strokes are a familiar bonding schematic; molecular-orbital theory is needed to explain O₂ paramagnetism.
The O₂ molecule tab retains the interactive 3D/electronic-structure teaching view.[He] 2s² 2p⁴
Hund’s rule fills equal-energy p orbitals singly before pairing. The O₂ molecular story is related but requires molecular orbitals built from two atoms.
Two unpaired electrons
In the ground-state molecular-orbital description, two electrons occupy separate degenerate π* antibonding orbitals with parallel spins. That gives O₂ a net magnetic moment.
Where do I meet oxygen?
Clickable learning cards connect oxygen to atmosphere, water, biology, metallurgy, medicine and oxidation chemistry.
O₂ is a major component of Earth’s air
Atmospheric molecular oxygen is central to aerobic respiration and many combustion processes, while oxygen atoms are even more abundant overall when water and rocks are included.
Why is oxygen paramagnetic?
A simple paired-electron Lewis structure does not display the ground-state spin arrangement. Molecular-orbital theory leaves two electrons unpaired in separate π* orbitals.
O₂, oxide, peroxide and ozone are different oxygen stories
The same element appears in multiple molecular and ionic environments. Use the selector to keep elemental oxygen separate from oxygen-containing compounds and allotropes.
O₂ · a covalent diatomic molecule
Two oxygen atoms form molecular orbitals together. Bond order and magnetism are molecular properties, not simply two isolated 2p⁴ atoms sitting side by side.
Molecular modelOxygen properties: atomic, molecular, chemical and isotope context
Reference values must distinguish isolated atomic quantities from properties of O₂ and from oxidation-state conventions inside compounds.
| Atomic number | 8 | Number of protons. |
|---|---|---|
| Relative atomic mass | 15.999 | Natural isotope-weighted display. |
| Electron configuration | [He] 2s² 2p⁴ | Neutral ground-state atom. |
| Electronegativity | 3.44 | Pauling scale. |
| Non-bonded atomic radius | 1.52 Å | RSC reference. |
| 1st ionization energy | 1313.942 kJ/mol | Ground-state gaseous atom. |
| Ordinary elemental form | O₂ | Diatomic molecular gas. |
|---|---|---|
| Ground-state magnetic behavior | Paramagnetic | Two unpaired electrons in π* orbitals. |
| Melting point | 54.36 K | Normal reference. |
| Boiling point | 90.188 K | Normal reference. |
| O=O bond enthalpy | 498.3 kJ/mol | RSC reference. |
| Common oxidation state | −2 | Common in ordinary oxides; not universal. |
|---|---|---|
| Peroxides | −1 per oxygen | O–O unit changes formal bookkeeping. |
| Representative compounds | H₂O, CO₂, Fe₂O₃ | Oxygen spans molecular and solid-state chemistry. |
| Allotrope | O₃ | Ozone has different geometry/reactivity from O₂. |
| ¹⁶O | 99.757% | Stable · dominant natural isotope. |
|---|---|---|
| ¹⁷O | 0.038% | Stable. |
| ¹⁸O | 0.205% | Stable. |
Oxygen state at temperature: solid → liquid → gas
O₂ has a normal cryogenic liquid interval at approximately standard pressure. The controller keeps the Carbon prototype’s visual depth while using the scientifically appropriate three-state path.
All three states shown here occur below room temperature except the familiar gas state. Liquid oxygen is pale blue and strongly paramagnetic, but this controller focuses on phase rather than attempting to simulate every optical or magnetic detail.
At 90 K O₂ is just below its normal boiling reference.Interactive oxygen cycle: atmosphere, water, life and rocks
Oxygen atoms move among molecular O₂, water, biomass and minerals. Click a reservoir to connect atmospheric oxygen to the much larger oxygen inventory bound in Earth materials.
Oxygen geography: atmosphere, oceans and rocks are global reservoirs
A country production map would be the wrong model for natural oxygen occurrence. The page uses global Earth-system layers, following the Carbon prototype’s evidence-aware geography approach.
Oxygen history: discovery, combustion and industrial air separation
Scheele
Prepared oxygen independently; the exact priority story is historically nuanced.
Priestley
Prepared and studied the gas he called “dephlogisticated air.”
Lavoisier
Explained oxygen’s role in combustion and helped overturn phlogiston theory.
Air separation
Industrial cryogenic separation enabled large-scale oxygen supply.
Essential industrial gas
Steelmaking, chemical manufacture, medicine and treatment systems use controlled oxygen supplies.
How commercial oxygen is produced
Large-scale oxygen is commonly separated from air. The route depends on purity and scale; this is a high-level process map, not operating instructions.
Take in air
Atmospheric air provides the feed mixture of nitrogen, oxygen, argon and trace gases.
Clean + condition
Water, carbon dioxide and contaminants are removed as required by the process.
Separate components
Cryogenic distillation or adsorption-based processes exploit physical-property differences among gases.
Deliver safely
Oxygen is supplied as gas or cryogenic liquid with equipment designed for strong oxidizer service.
Where oxygen is used
Steelmaking
Commercial oxygen supports high-temperature refining and oxidation control in steel production.
Medicine
Used in controlled respiratory support and clinical gas systems.
Chemical manufacture
Oxygen and oxygen-containing oxidants support many industrial syntheses.
Water treatment
Oxygen transfer supports biological wastewater-treatment processes.
Cutting + combustion
Oxygen-rich conditions can intensify selected industrial combustion processes.
Oxidizer systems
Liquid oxygen is used as an oxidizer in selected aerospace propulsion systems.
Water, oxides, peroxides and ozone
Water
Oxygen commonly forms two covalent bonds in neutral H₂O.
Oxides
Many metal oxides use formal oxygen oxidation state −2.
Peroxides
The O–O unit gives formal oxygen oxidation state −1 in simple peroxide bookkeeping.
Ozone
An allotrope with different geometry, reactivity and atmospheric roles from O₂.
Oxygen-16, oxygen-17 and oxygen-18
Five-question Oxygen check
How many valence electrons does neutral oxygen have?
Why is ground-state O₂ paramagnetic?
Which isotope dominates natural oxygen?
What is oxygen’s common oxidation state in ordinary oxides?
At room temperature, elemental oxygen is mainly what state?
Oxygen questions: quick answer first, then the mechanism
The page separates atomic electron configuration, molecular O₂ electronic structure, oxidation-state bookkeeping and Earth-system occurrence.
Why is oxygen paramagnetic?
Short answer: Ground-state O₂ has two unpaired electrons in separate π* antibonding molecular orbitals.
Unpaired electron spins produce a net magnetic moment, so molecular oxygen is attracted by a magnetic field. This is a classic case where molecular-orbital theory explains an observation that a simple paired-electron Lewis picture can obscure.
How many valence electrons does oxygen have?
Short answer: Six.
The [He] 2s² 2p⁴ configuration puts six electrons in the n=2 valence shell. That supports common two-bond patterns while still allowing broader oxidation-state chemistry.
Is oxygen flammable? Why does it support combustion without being the fuel?
Short answer: Oxygen is not normally classified as the fuel; O₂ is the oxidizing reactant that allows many fuels to burn rapidly.
Combustion is a redox process involving at least two reacting partners. The fuel is oxidized while oxygen is reduced into products such as oxides, CO₂ or H₂O. Raising the oxygen concentration can make materials ignite more readily and burn much faster, which is why oxygen-rich environments create severe fire hazards even though the oxygen itself is not described as “burning.”
The distinction is chemical-object specific: molecular O₂ is an oxidizer under ordinary combustion conditions. Saying “oxygen is flammable” confuses the oxidizer with the material being oxidized.
Key point: Oxygen supports and accelerates combustion because it is the oxidizer; the fuel is the species being oxidized.
Where is oxygen found naturally?
Short answer: In air, water, rocks, minerals and living systems.
Free O₂ is a major atmospheric component, but oxygen atoms are even more widespread in H₂O, silicates, oxides and biological molecules. That is why a single country-dot occurrence map would be misleading.
Is liquid oxygen magnetic?
Short answer: Yes, liquid O₂ is paramagnetic.
The magnetic response comes from the unpaired electrons of O₂ molecules. The temperature controller focuses on phase, while the signature module explains the electronic origin of the magnetism.
Scientific sources for Oxygen
Core atomic, isotope, molecular and phase statements are tied to authoritative scientific sources. Earth geography is presented as global reservoirs rather than invented country occurrence rankings.
Questions to ask next about Oxygen
A good element lesson should lead to the next useful question, not end after a list of facts.
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