Periodic Table > Oxygen
 

Terminology


Allotropes
Some elements exist in several different structural forms, these are called allotropes.


For more information on Murray Robertson’s image see Uses/Interesting Facts below.

 

Fact Box Terminology


Group
Elements appear in columns or ‘groups’ in the periodic table. Members of a group typically have similar properties and electron configurations in their outer shell.


Period
Elements are laid out into rows or ‘periods’ so that similar chemical behaviour is observed in columns.


Block
Elements are organised into blocks by the orbital type in which the outer electrons are found. These blocks are named for the characteristic spectra they produce: sharp, principal, diffuse, and fundamental.


Atomic Number
The number of protons in the nucleus.


Atomic Radius/non -bonded (Å)
based on Van der Waals forces (where several isotopes exist, a value is presented for the most prevalent isotope). These values were calculated using a multitude of methods including crystallographic data, gas kinetic collision cross sections, critical densities, liquid state properties, for more details please refer to the CRC Handbook of Chemistry and Physics.


Electron Configuration
The arrangements of electrons above the last (closed shell) noble gas.


Isotopes
Elements are defined by the number of protons in its centre (nucleus), whilst the number of neutrons present can vary. The variations in the number of neutrons will create elements of different mass which are known as isotopes.


Melting Point (oC)
The temperature at which the solid-liquid phase change occurs.


Melting Point (K)
The temperature at which the solid-liquid phase change occurs.


Melting Point (oF)
The temperature at which the solid-liquid phase change occurs.


Boiling Point (oC)
The temperature at which the liquid-gas phase change occurs.


Boiling Point (K)
The temperature at which the liquid-gas phase change occurs.


Boiling Point (oF)
The temperature at which the liquid-gas phase change occurs.


Sublimation
Elements that do not possess a liquid phase at atmospheric pressure (1 atm) are described as going through a sublimation process.


Density (kgm-3)
Density is the weight of a substance that would fill 1 m3 (at 298 K unless otherwise stated).


Relative Atomic Mass
The mass of an atom relative to that of Carbon-12. This is approximately the sum of the number of protons and neutrons in the nucleus. Where more than one isotope exists the value given is the abundance weighted average.


Key Isotopes (% abundance)
An element must by definition have a fixed number of protons in its nucleus, and as such has a fixed atomic number, however variants of an element can exist with differing numbers of neutrons, and hence a different atomic masses (e.g. 12C has 6 protons and 6 neutrons and 13C has 6 protons and 7 neutrons).


CAS number
The Chemical Abstracts Service registry number is a unique identifier of a particular chemical, designed to prevent confusion arising from different languages and naming systems (where several isotopes exist, a value is presented for the most prevalent isotope).

Fact Box

 
Group 16  Melting point -218.79 oC, -361.822 oF, 54.36 K 
Period Boiling point -182.962 oC, -297.332 oF, 90.188 K 
Block Density (kg m-3) 1460 (20.5 K) 
Atomic number Relative atomic mass 15.999  
State at room temperature Gas  Key isotopes 16
Electron configuration [He] 2s22p4  CAS number 7782-44-7 
ChemSpider ID 140526 ChemSpider is a free chemical structure database
 

Interesting Facts terminology


Image Explanation

Murray Robertson is the artist behind the images which make up Visual Elements. This is where the artist explains his interpretation of the element and the science behind the picture.


Natural Abundance

Where this element is most commonly found in nature.


Biological Roles

The elements role within the body of humans, animals and plants. Also functionality in medical advancements both today and years ago.


Appearance

The description of the element in its natural form.

Uses / Interesting Facts

 
Image explanation
Ozone and iced water. An image representing the fundamental importance of the element in air and water.
Appearance

A colourless, odourless gas.

Source

Uses

Industrially, oxygen is produced on a large scale from liquid air by liquefaction and fractional distillation.  In the laboratory it can be prepared by the electrolysis of water or by adding manganese(IV) oxide as a catalyst to aqueous hydrogen peroxide. Oxygen is very reactive and capable of combining with most other elements. It is a component of thousands of organic compounds, and is essential for the aerobic respiration of all plants and animals and for almost all combustion.  The greatest commercial use of gaseous oxygen is in the steel industry. Large quantities are also used in the manufacture of epoxyethane, nitric acid, hydrogen peroxide and chloroethene, the precursor to PVC and for oxy-acetylene welding and cutting of metals. A growing use is in the treatment of sewage and of effluent from industry.

Biological role

Oxygen gas is fairly soluble in water, which makes aerobic life in rivers, lakes and oceans possible. Oxygen first appeared as a constituent of Earth's atmosphere around 2 billion years ago, when sufficient oxygen from the photosynthesis of blue-green algae had accumulated. In this process energy from the Sun splits water into oxygen, which passes into the atmosphere and hydrogen, which joins with carbon dioxide to produce biomass. When living things need energy they take in oxygen so that it can react in their cells with the biomass absorbed by digestion of food; they then return that oxygen to the atmosphere in the form of carbon dioxide. We, for example, breathe in oxygen so that it can react with the fuel (food) in our bodies allowing the transfer of energy for our cells that keeps us alive, active and warm. We breathe out the carbon dioxide that forms. 

Natural abundance

Oxygen, as a gaseous element, forms 21% of the atmosphere by volume, which is half-way between 17% (below which breathing for unaclimatised people becomes difficult) and 25% (above which many organic compounds are highly flammable). The element and its compounds make up 49.2%, by mass of the Earth’s crust, about two-thirds of the human body and nine-tenths of water.

 
Atomic Data Terminology

Atomic radius/non -bonded (Å)
Based on Van der Waals forces (where several isotopes exist, a value is presented for the most prevalent isotope). These values were calculated using a multitude of methods including crystallographic data, gas kinetic collision cross sections, critical densities, liquid state properties,for more details please refer to the CRC Handbook of Chemistry and Physics.


Electron affinity (kJ mol-1)
The energy released when an additional electron is attached to the neutral atom and a negative ion is formed (where several isotopes exist, a value is presented for the most prevalent isotope). *


Electronegativity (Pauling scale)
The degree to which an atom attracts electrons towards itself, expressed on a relative scale as a function bond dissociation energies, Ed in eV. χA - χB =(eV)-1/2sqrt(Ed(AB)-[Ed(AA)+Ed(BB)]/2), with χH set as 2.2 (where several isotopes exist, a value is presented for the most prevalent isotope).


1st Ionisation energy (kJ mol-1)
The minimum energy required to remove an electron from a neutral atom in its ground state (where several isotopes exist, a value is presented for the most prevalent isotope).


Covalent radius (Å)
The size of the atom within a covalent bond, given for typical oxidation number and coordination (where several isotopes exist, a value is presented for the most prevalent isotope). ***

Atomic Data

 
Atomic radius, non-bonded (Å) 1.520 Covalent radius (Å) 0.64
Electron affinity (kJ mol-1) 140.926 Electronegativity
(Pauling scale)
3.440
Ionisation energies
(kJ mol-1)
 
1st
1313.942
2nd
3388.668
3rd
5300.466
4th
7469.264
5th
10989.574
6th
13326.515
7th
71330.586
8th
84078.228
 
Bonding and Enthalpies terminology

Covalent Bonds
The strengths of several common covalent bonds.

Bonding / Enthalpies

 
Covalent bonds
N–O  214  kJ mol -1 N=O  587  kJ mol -1 O–O  144  kJ mol -1
O–O  302  kJ mol -1 O=O  498.3  kJ mol -1 O–Si  466  kJ mol -1
O=Si  638  kJ mol -1 O≡Si  805  kJ mol -1 H–O  464  kJ mol -1
C–O  358  kJ mol -1 C–O  336  kJ mol -1 C=O  805  kJ mol -1
C=O  695  kJ mol -1 C=O  736  kJ mol -1 C=O  749  kJ mol -1
C≡O  1077  kJ mol -1 O=S  469  kJ mol -1  
 

Mining/Sourcing Information

Data for this section of the data page has been provided by the British Geological Survey. To review the full report please click here or please look at their website here.


Key for numbers generated


Governance indicators

1 (low) = 0 to 2

2 (medium-low) = 3 to 4

3 (medium) = 5 to 6

4 (medium-high) = 7 to 8

5 (high) = 9


Reserve base distribution

1 (low) = 0 to 30 %

2 (medium-low) = 30 to 45 %

3 (medium) = 45 to 60 %

4 (medium-high) = 60 to 75 %

5 (high) = 75 %

(Where data are unavailable an arbitrary score of 2 was allocated. For example, Be, As, Na, S, In, Cl, Ca and Ge are allocated a score of 2 since reserve base information is unavailable. Reserve base data are also unavailable for coal; however, reserve data for 2008 are available from the Energy Information Administration (EIA).)


Production Concentration

1 (low) = 0 to 30 %

2 (medium-low) = 30 to 45 %

3 (medium) = 45 to 60 %

4 (medium-high) = 60 to 75 %

5 (high) = 75 %


Crustal Abundance

1 (low) = 100 to 1000 ppm

2 (medium-low) =10 to 100 ppm

3 (medium) = 1 to 10 ppm

4 (medium-high) = 0.1 to 1 ppm

5 (high) = 0.1 ppm

(Where data are unavailable an arbitrary score of 2 was allocated. For example, He is allocated a score of 2 since crustal abundance data is unavailable.)


Explanations for terminology


Crustal Abundance (ppm)

The abundance of an element in the Earth's crust in parts-per-million (ppm) i.e. The number of atoms of this element per 1 million atoms of crust.


Sourced

The country with the largest reserve base.


Reserve Base Distribution

This is a measure of the spread of future supplies, recording the percentage of a known resource likely to be available in the intermediate future (reserve base) located in the top three countries.


Production Concentrations

This reports the percentage of an element produced in the top three countries. The higher the value, the larger risk there is to supply.


Total Governance Factor

The World Bank produces a global percentile rank of political stability. The scoring system is given below, and the values for all three production countries were summed.


Relative Supply Risk Index

The Crustal Abundance, Reserve Base Distribution, Production Concentration and Governance Factor scores are summed and then divided by 2, to provide an overall Relative Supply Risk Index.

Supply Risk

 
Scarcity factor Unknown
Country with largest reserve base Unknown
Crustal abundance (ppm) Unknown
Leading producer Unknown
Reserve base distribution (%) n/a
Production concentration (%) Unknown
Total governance factor(production) Unknown
Top 3 countries (mined)
  • Unknown
Top 3 countries (production)
  • Unknown
 

Oxidation states/ Isotopes


Key for Isotopes


Half Life
  y years
  d days
  h hours
  m minutes
  s seconds
Mode of decay
  α alpha particle emission
  β negative beta (electron) emission
  β+ positron emission
  EC orbital electron capture
  sf spontaneous fission
  ββ double beta emission
  ECEC double orbital electron capture

Terminology


Common Oxidation states
The oxidation state of an atom is a measure of the degree of oxidation of an atom. It is defined as being the charge that an atom would have if all bonds were ionic. Free atoms have an oxidation state of 0, and the sum of oxidation numbers within a substance must equal the overall charge.


Important Oxidation states
The most common oxidation states of an element in its compounds.


Isotopes
Elements are defined by the number of protons in its centre (nucleus), whilst the number of neutrons present can vary. The variations in the number of neutrons will create elements of different mass which are known as isotopes.

Oxidation States / Isotopes

 
Common oxidation states -1, -2
Isotopes Isotope Atomic mass Natural abundance (%) Half life Mode of decay
  16O 15.995 99.757
  17O 16.999 0.038
  18O 17.999 0.205
 

Pressure and Temperature - Advanced Terminology


Molar Heat Capacity (J mol-1 K-1)

Molar heat capacity is the energy required to heat a mole of a substance by 1 K.


Young's modulus (GPa)

Young's modulus is a measure of the stiffness of a substance, that is, it provides a measure of how difficult it is to extend a material, with a value given by the ratio of tensile strength to tensile strain.


Shear modulus (GPa)

The shear modulus of a material is a measure of how difficult it is to deform a material, and is given by the ratio of the shear stress to the shear strain.


Bulk modulus (GPa)

The bulk modulus is a measure of how difficult to compress a substance. Given by the ratio of the pressure on a body to the fractional decrease in volume.


Vapour Pressure (Pa)

Vapour pressure is the measure of the propensity of a substance to evaporate. It is defined as the equilibrium pressure exerted by the gas produced above a substance in a closed system.

Pressure / Temperature - Advanced

 
Molar heat capacity
(J mol-1 K-1)
29.378 Young's modulus (GPa) Unknown
Shear modulus (GPa) Unknown Bulk modulus (GPa) Unknown
Vapour pressure  
Temperature (K)
400 600 800 1000 1200 1400 1600 1800 2000 2200 2400
Pressure (Pa)
- - - - - - - - - - -
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History

In 1608, Cornelius Drebbel had shown that heating saltpetre (potassium nitrate, KNO3) released a gas. This was oxygen although it was not identified as such.


The credit for discovering oxygen is now shared by three chemists: an Englishman, a Swede, and a Frenchman. Joseph Priestley was the first to publish an account of oxygen, having made it in 1774 by focussing sunlight on to mercuric oxide (HgO), and collecting the gas which came off. He noted that a candle burned more brightly in it and that it made breathing easier. Unknown to Priestly, Carl Wilhelm Scheele had produced oxygen in June 1771. He had written an account of his discovery but it was not published until 1777. Antoine Lavoisier also claimed to have discovered oxygen, and he proposed that the new gas be called oxy-gène, meaning acid-forming, because he thought it was the basis of all acids.

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Podcasts

Listen to Oxygen Podcast
Transcript :

Chemistry in Its Element - Oxygen


(Promo)

 

You're listening to Chemistry in its element brought to you by Chemistry World, the magazine of the Royal Society of Chemistry.

 

(End promo)

 

Chris Smith

Hello! And welcome to Chemistry in its element, where we take a look at the stories behind the elements that make up the world around us. I'm Chris Smith. This week, we are continuing our tour of the periodic table with a lung full of a gas that we can't do without. It protects us from solar radiation, it keeps us alive and by helping things to burn, it also keeps us warm. It is of course Oxygen. And to tell its story, here's Mark Peplow.

 

Mark Peplow

Little did those humble Cyanobacteria realize what they were doing when two and a half billion years ago, they started to build up their own reserves of energy-rich chemicals, by combining water and Carbon dioxide. Powered by sunlight, they spent the next two billion years terraforming our entire planet with the waste products of their photosynthesis, a rather toxic gas called Oxygen. In fact, those industrious bugs are ultimately responsible for the diversity of life, we see around us today. Oxygen accounts for about 23% of the atmosphere's mass with pairs of Oxygen atoms stuck together to make Dioxygen molecules, but it's not just in the air, we breathe. Overall, it's the most abundant element on the earth's surface and the third most abundant in the universe after Hydrogen and Helium. Our planet's rocks are about 46% Oxygen by weight, much of it in the form of Silicon dioxide, which we know most commonly as sand. And many of the metals we mine from the Earth's crust are also found as their oxides, Aluminium in bauxite or Iron in hematite, while carbonates such as limestone are also largely made of Oxygen and the oceans are of course about 86% Oxygen, connected to Hydrogen as good old H2O, just about the most perfect solvent you can imagine for biochemistry. Oxygen is also in virtually every molecule in your body including fats, carbohydrates and DNA. In particular, it's the atom that links together the phosphate groups in the energy-carrying molecule ATP. Oxygen is obviously pretty useful for keeping us going, but is also widely used in industry as an oxidant, where it can give up some of that solar energy captured by plant and those Cyanobacteria. A stream of Oxygen can push the temperature of a blast furnace over 2000 degrees and it allows an oxyacetylene torch to cut straight through metal. The space shuttle is carried into space on an incredible force produced when liquid Oxygen and liquid Hydrogen combine to make water.

 

So who first noticed this ubiquitous stuff? There's certainly some debate about who first identified Oxygen as an element, partly because at the time the precise definition of an element still hadn't really been pinned down. English chemist, Joseph Priestley certainly isolated Oxygen gas in the 1770s, although he tried to define it as dephlogisticated air. Phlogiston was then thought to be some kind of primordial substance that was the root cause of combustion. Swedish chemist, Carl Wilhelm Scheele was a fan of phlogiston too and probably discovered Oxygen before Priestly did. But it was Antoine Lavoisier, sometimes called the father of modern chemistry, who was the first to truly identify Oxygen as an element and in doing so, he really helped to firm up the definition that an element is something that cannot be broken down by any kind of chemical analysis. This also helped him to kill off the phlogiston theory, which was a crucial step in the evolution of chemistry. 

 

Oxygen isn't only about the Dioxygen molecules that sustain us. There is another form, Trioxygen, also known as ozone and it's also pretty important in the upper reaches of the atmosphere, is responsible for filtering out harmful ultraviolet rays, but unfortunately, ozone is also pretty toxic. So it's bad news that tons of the gas are produced by the reactions between hydrocarbons and Nitrogen oxides churned out by cars every day. If only we could transplant the stuff, straight up into the stratosphere! Now ozone is normally spread so thinly in the air, that you can't see its pale blue colour and Oxygen gas is colourless unless you liquefy it, but there is one place where you can see the gas in all its glory. The aurora or polar lights, where particles from the solar wind slam into Oxygen molecules in the upper atmosphere to produce the swirling green and red colours that have entranced humans for millennia.

 

Chris Smith

So why life is a gas, that was Mark Peplow revealing the secrets of the element that we can't live without. Next time on Chemistry in its element, Johnny Ball joins us to tell the story of a chemical that's craved by Olympic athletes, makes good hi-five connectors and is also a favourite for fillings. And that's in teeth, not pies.

 

Johnny Ball

Today one gram can be beaten into a square meter sheet just 230 atoms thick, one cubic centimetre would make a sheet 18 square meters, 1gm could be drawn out to make 165 meters of wire just 1/200th of a millimetre thick. The gold colour in Buckingham Palace fence is actually Gold; Gold covered because it lasts 30 years; whereas gold paint which actually contains no gold at all lasts in tick-tock condition only a year or so.

 

Chris Smith

So all that glitters isn't gold, but some is, and you can find out why on next week's Chemistry in its element. I'm Chris Smith, thanks for listening.   See you next time.

 

(Promo)

 

Chemistry in its elementis brought to you by the Royal Society of Chemistry and produced by thenakedscientists dot com. There's more information and other episodes of Chemistry in its element on our web site at chemistryworld dot org forward slash elements.

 

(End promo) 

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  Help Text

Resources

Description :
Potassium manganate(VII) produces oxygen when heated. In this experiment oxygen is produced and identified with a glowing splint.
Description :
In the beaker are test-tubes containing different gases - carbon dioxide, dinitrogen oxide, oxygen, chlorine and hydrogen. You may remove a test-tube only once and when you do so you must identify th...
Description :
An introduction to the common elements found in the Earth's crust. This can be used to underpin topics on useful materials from the Earth and on the extraction of metals.
Description :
Gives information about the most common elements in the Earth’s crust and the other the chemical composition of some minerals.
Description :
In this experiment you will be generating oxygen gas by reacting hydrogen peroxide and potassium manganate(VII) and testing for it using methylene blue solution.
Description :
This demonstration involves electrolysing sulfuric acid and the explosive re-combination of the hydrogen and oxygen and can be used if you school doesn’t have soldering equipment. Please note this me...
 

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References

 
Images:  Visual Elements © Murray Robertson 2011
Mining and Sourcing data:  British Geological Survey – natural environment research council.
Text:  John Emsley Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, 2nd Edition, 2011.
Additional information for platinum, gold, neodymium and dysprosium obtained from Material Value Consultancy Ltd www.matvalue.com
Data: CRC Handbook of Chemistry and Physics, CRC Press, 92nd Edition, 2011.
G. W. C. Kaye and T. H. Laby Tables of Physical and Chemical Constants, Longman, 16th Edition, 1995.
Members of the RSC can access these books through our library.