Oxygen Chemical Properties (23 Facts You Should Know)

Oxygen is one of the most significant and abundant elements present on the earth. Being an element of importance, let us discuss various facts related to it in this article.

Oxygen is a diatomic and odorless gas and is a major source of thriving life and other biological and ecological phenomena on the planet earth. Its existence on earth is in the form of various oxides due to its chemical flexibility and easy binding properties.

Oxygen is the basis of various interdisciplinary sciences and is foundational in the development of organic chemistry and its related studies. The evolutionary theories regarding the origin of life are very much based on oxygen. Let us analyze oxygen’s periodic classifications and chemical properties.

Oxygen symbol

The symbol for oxygen is O which is the first letter of the element as decided by the atomic theory but in nature it is presented as O2 which is its diatomic form.

oxygen chemical properties
Symbol of diatomic oxygen

Oxygen group in the periodic table

Oxygen belongs to group 16 of the periodic table which is famously called the chalkogen familie.

Oxygen period in the periodic table

Oxygen is located in the 2nd period of the periodic table which follows the decreasing metallic trend and is a non-metal.

Oxygen block in the periodic table

Oxygen is situated in the p-blok of the periodic table which highlights the non-metallic character and high electron gain enthalpy of oxygen.

Oxygen atomic number

Die atoomgetal of oxygen is 8 because it has 8 protons.

Oxygen electronegativity according to Pauling

Die elektronegatiwiteit of oxygen according to the Pauling scale is 3.44 which is the second highest which implies high electron attracting capacity as it needs only 2 electrons to complete its octet.

Oxygen atomic density

The atomic density of oxygen is 1.429 g/cm3 which explains the volumetric and spatial capacity of the element.

Oxygen melting point

The melting point of oxygen is -218 degree Celsius which is quite low because it is covalently bonded which is a weak bonding and does not require much energy.

Oxygen boiling point     

The boiling point of oxygen is -183 degree Celsius which like its melting point is very low due to the molecular forces between them.

Oxygen van der Waals radius

Die van der Waals radius of oxygen is 152 pm as can be judged from its bonding abilities.

Oxygen ionic/covalent radius

Die kovalente radius of oxygen is 66 pm with an error of +2 or -2 which results in stable diatomic oxygen molecules by double covalent bonding.

Oxygen isotopes

Isotopes are formed when there is variation in the no. of subatomic particles in the same chemical element. Let us discuss the no. of isotopes formed in oxygen.

Oxygen has 3 stable isotope and 18 radioactive isotopes with the shortest half-life. The most stable isotopes of oxygen are:

  • 16O
  • 17O
  • 18O

Oxygen electronic shells

Electronic shells are the energy levels that accommodate electrons. Let us discuss the same for oxygen.

Oxygen has 2 electronic shells which complete its octet, and the broader configuration is 2, 6.

Oxygen energy of first ionization

Die eerste ionisasie-energie of oxygen is 13.6181 eV which is quite low because it is half-filled stable, and one electron is added afterward forcefully which makes its removal easy.

Oxygen energy of second ionization

The second ionization energy of oxygen is 3388.3 eV which is quite high because after the removal of the first electron, the configuration achieves half-filled stability which makes the removal of the electron harder and needs more energy.

Oxygen energy of third ionization

The third ionization energy of oxygen is even higher which is 5300.5 eV.

Oxygen oxidation states

Oxygen has 7 oksidasie toestande which are highly influenced by the type of element it is reacting with and the compound formed. These oxidation states and the desired compounds formed are:

  • -2 in oxides
  • -1 in peroxides
  • -½ in superoxides
  • -⅓ in ozonides or ozone-like compounds
  • +½ where oxygen acts as a cation in compounds
  • +1 in oxygen monofluoride
  • +2 in oxygen difluoride

Oxygen electron configurations

The electronic configuration of oxygen satisfying all the quantum numbers is [He]2s22p4 where He is the noble gas helium.

Oxygen CAS number

Die MAS-nommer designated to the oxygen element is 7782-44-7.

Oxygen ChemSpider ID

ChemSpider ID of oxygen is 140526.

Oxygen allotropic forms

Allotropic forms are those which have the same chemical compositions but different physical structures. Let us discuss allotropie in oxygen.

There are commonly 4 allotropic forms of oxygen which are:

  • Dioxygen O2 which is colorless
  • Osoon O3 which is blue
  • Tetraoxygen O4 is responsible for the red hue.
  • Metallic oxygen exists at very high-pressure conditions.

Oxygen chemical classifications

Various chemical properties associated with oxygen are:

  • Oxygen is a colorless and odorless gas that has no taste as well.
  • Due to the chemical properties of oxygen, it is a highly reactive non-metal and can readily form oxides with all the elements, noble gases being an exception.
  • Oxygen is one of the few and rare gases which can undergo combustion.
  • Oxygen is a non-metal gas of value as it is required for life to exist on earth.
3D representation of oxygen molecule

Oxygen state at room temperature

Oxygen is gas at room temperature due to low melting and boiling points and exists as diatomic molecular gas.

Is Oxygen paramagnetic?

The magnetic character of any element depends on the electron pairing and the external field applied. Let us find out whether paramagnetisme is observed in oxygen or not.

Oxygen is paramagnetic because of the presence of 2 unpaired electrons in its molecular orbital.


In a nutshell, oxygen is an important element in the periodic table which is amiable with all the properties required for various scientific activities which can be biological, chemical, physical, and ecological.


Mansi Sharma

Hallo, ek is Mansi Sharma, ek het my meestersgraad in Chemie voltooi. Ek glo persoonlik dat leer meer entoesiasties is as dit met kreatiwiteit geleer word. Ek is 'n vakkundige in chemie. Kom ons koppel deur LinkedIn: https://www.linkedin.com/in/mansi-sharma22

Onlangse plasings