Periodic Table

Oxygen

Nonmetal

Quick Facts about Oxygen

N
  • gas- state of matter at room temperature
  • Stable- has at least one stable isotope
  • -2- common oxidation states in compounds
  • CUB- crystal structure, atomic arrangement in solid form
F

Oxygen (O) is element 8 on the periodic table. Atomic mass of O: 15.9990 u. O is in period 2, group 16. Melting point of O: 54.36 K.Density of O: 0.00 g/cm³.

Why Oxygen Matters

Every breath you take contains the element that keeps you alive

In Your Home

  • The air you breathe is 21% oxygen
  • Water in your taps (H2O)
  • Bleach and cleaning products
  • Rust on your car, bike, or tools (iron oxide)

Industry Uses

HealthcareMedical oxygen for patients, anesthesia, and respiratory therapy
SteelOxygen furnaces produce 70% of world's steel
AerospaceLiquid oxygen (LOX) as rocket oxidizer
WeldingOxy-acetylene torches cut through metal

In Your Body

✓ Essential for life

Essential for cellular respiration—converts glucose to energy. Makes up 65% of human body mass (mostly in water). Required by all aerobic organisms.

Safety: Pure oxygen is toxic at high pressures (oxygen toxicity). Normal atmospheric levels (21%) are safe.

Discovery of Oxygen

Discovered by Joseph Priestly, Carl Wilhelm Scheele in England/Sweden, 1774

Name origin: Greek: oxys and genes, (acid former).

History & Events

1774
Discovery
Joseph Priestley isolated 'dephlogisticated air' by heating mercury oxide
1967
Apollo 1 Fire
Pure oxygen atmosphere caused fatal fire during launch pad test, killing 3 astronauts
1957
Hyperbaric Medicine
First hyperbaric oxygen chambers used to treat decompression sickness

About Oxygen

A colorless, odorless gaseous element belonging to group 16 of the periodic table. It is the most abundant element present in the earth's crust. It also makes up 20.8% of the Earth's atmosphere. For industrial purposes, it is separated from liquid air by fractional distillation. It is used in high temperature welding, and in breathing. It commonly comes in the form of Oxygen, but is found as Ozone in the upper atmosphere. It was discovered by Priestley in 1774.

Atomic Properties of O

Atomic Number of O
8
Atomic Mass of O
15.9990 u
Electron Configuration
[He] 2s2 2p4
Electronegativity
3.44
Block
p-block
Group
16
Period
2

Physical Properties of O

Phase (STP)
gas
Melting Point of O
54.36 K
Boiling Point of O
90.19 K
Density of O
0.0014 g/cm3

Thermal Properties

Specific Heat
0.92 J/g·K
Molar Heat Capacity
29.38 J/mol·K
Thermal Conductivity
0.03 W/m·K

Atomic Radii

Calculated
60 pm
Covalent
63 pm
Van der Waals
152 pm

Common Misconceptions

Wrong:We breathe in oxygen and breathe out carbon dioxide.
Correct:We exhale mostly nitrogen (78%), with 16% oxygen and only 4% CO2. We don't use all the oxygen we inhale.
Wrong:Plants produce oxygen during the day and CO2 at night.
Correct:Plants always respire (use O2, release CO2), but photosynthesis during the day produces more O2 than respiration uses.
Wrong:Oxygen is flammable.
Correct:Oxygen doesn't burn—it's an oxidizer that makes other things burn faster and hotter.

Allotropes of Oxygen

Oxygen exists in 3 different structural forms (allotropes), each with unique properties.

Dioxygen (O2)

Common oxygen gas we breathe

Structure:Diatomic molecule with double bond
Properties:Colorless, odorless, paramagnetic, essential for respiration
Uses:Respiration, combustion, medical oxygen, steel production

Ozone (O3)

Triatomic oxygen with distinctive sharp smell

Structure:Bent molecule with resonance structures
Properties:Pale blue gas, powerful oxidizer, absorbs UV light
Uses:Water purification, sterilization, UV protection in stratosphere

Tetraoxygen (O4)

Rare metastable form

Structure:Weakly bound O2 dimer
Properties:Exists at very low temperatures or high pressures

Isotopes of Oxygen

Oxygen has 3 naturally occurring isotopes.

IsotopeAtomic Mass (u)AbundanceHalf-LifeDecay Mode
168O (O-16)Oxygen-16 isotope15.9949146299.76%
178O (O-17)Oxygen-17 isotope16.999131760.0380%
188O (O-18)Oxygen-18 isotope17.999159610.2050%

Data source: NIH PubChem (aggregated from IUPAC, NIST)

Isotope Applications

Isotopes of Oxygen have important real-world applications in science and industry.

Medical Applications

16O is used to produce radioactive 13N via the 16O (p, 4He) 13N reaction for imaging in positron emission tomography (PET) and to study blood flow through the heart (myocardial perfusion) [94], [95]. 17O has been used as a tracer to study cerebral oxygen utilization [96]. Variations in stable oxygen and hydrogen isotopes are used in energy expenditure studies in animals and humans. The subject is administered a dose of doubly labeled water (water enriched in both 2H and 18O). Measurements of the elimination rates of 2H and 18O in the subject over time through regular sampling of body water (by sampling saliva, urine, or blood) provide information on energy expenditure because the hydrogen isotopic composition of body water is affected primarily by water loss (mainly urination), but the oxygen isotopic composition is affected by both respiration and water loss [97].

Abundance

Earth's Crust
461.0 g/kg
Seawater
857.0 g/kg

Uses

Used in steel making, welding, and supporting life. Naturally occurring ozone (O3) in the upper atmosphere shields the earth from ultraviolet radiation.

Sources

Obtained primarily from liquid air by fractional distillation. Small amounts are made in the laboratory by electrolysis of water or heating potassium chlorate (KClO3) with manganese dioxide (MnO2) catalyst.

Geochemistry

Goldschmidt
litophile
Geochemical Class
major

Test Your Knowledge

Loading quiz...