Looking for oxygen facts, huh? Good! You shouldn’t ignore them. You might find them handy any moment. More importantly, oxygen is something that keeps us alive. So, this element does deserve some respect.

Did you know that oxygen levels in Earth’s atmosphere started increasing some 2.5 billion years ago? We don’t claim this. That’s what a study funded by NASA says.

The reason for the sudden increase in the levels of this gas in Earth’s atmosphere is not precisely known even to scientists but they do think that instead of oxygen being consumed in geological reactions, oxygen was produced by organisms that stuck around and participated in photosynthesis.

Whatever the reason be for the sudden rise in the levels of this gas, we should be glad because it is one of the prime factors that keep life humming on this blue orb that we call home. So, in honor of this gas, we are going to learn 55 oxygen facts, and find out a few things about what it really is and how it behaves.

You ready?

But before we start with oxygen facts sheet, let’s go through the isotopes of oxygen.

Isotope NameType and AbundanceHalf-Life (HL)
11ORadioactive[~3.4 MeV]
12ORadioactive> 6.3(30)×10−21 s
13ORadioactive8.58(5) ms
14ORadioactive70.620(13) s
15ORadioactive122.24(16) s
16OStable, 99.76% abundanceStable, so no HL
17OStable, 0.04% abundanceStable, so no HL
18OStable, 0.20% abundanceStable, so no HL
19ORadioactive26.470(6) s
20ORadioactive13.51(5) s
21ORadioactive3.42(10) s
22ORadioactive2.25(9) s
23ORadioactive97(8) ms
24ORadioactive77.4(45) ms
25ORadioactive5.18(0.35)×10−21 s
26ORadioactive4.2(3.3) ps


ms: milliseconds

s: seconds

ps: picoseconds

MeV: megaelectron volt (sometimes half-life is denoted in energy unit, which is electron volt).

Okay, now that we have the list of different isotopes, it is about time we start with the oxygen facts.

Oxygen Facts: 1-5

1. Oxygen is the 8th element in period table. Yes, it is an element and not a compound.

2. The atomic number of oxygen is 8. What is atomic number? It refers to the number of protons that are present in the nucleus of an atom of an element. So, there are 8 protons in a nucleus of an oxygen atom.

3. There are 8 electrons in an oxygen atom. Also, there are 8 neutrons in an atom of the most abundant type of oxygen.

4. Electronic configuration of oxygen is 1s22s22p4.

5. They symbol used to denote oxygen in the period table is O. That’s the letter O. It is not 0 (Zero).

Oxygen Facts: 6-10

6. In every cubic centimeter of space, you will find 0.001429 grams of oxygen. This is the density of the element.

7. The average mass of an oxygen atom stands at 15.9994. This mass is referred to as the Atomic Weight.

8. Sweden’s Carl W. Scheele was the person to discovered oxygen in 1772. However, he did not publish his discovery.

9. England’s Joseph Priestly independently discovered oxygen in 1774. He however, went on to publish his discovery, which gained him the credit of being the discoverer.

10. Scheele’s method of discovery included heating various compounds including mercury oxide, potassium nitrate, and manganese oxide. He found that when these compounds are heated, they release a gas that enhanced the combustion process.

Oxygen Facts: 11-15

11. Priestly’s method involved heating mercury oxide using a concentrated beam of sunlight. He used a 12-inch burning lens (a big magnifying glass). This increased the temperature of mercury oxide.

12. The hot compound released a gas that made a candle burn 5x faster than in normal conditions.

13. Priestly placed a mouse in a jar full of the unknown gas and expected the mouse to suffocate within 15 minutes, but to his surprise the mouse survived a whole hour. This led him to get a hint of the gas’ biological role.

14. Antoine Lavoisier performed several other experiments very similar to that of Priestly and found that the air contains about 20% oxygen.

15. Lavoisier also found out that when a substance burns, it combines with oxygen chemically.

Oxygen Facts: 16-20

16. Lavoisier found various other things. He found that the weight of the gas that is released by heating mercury oxide was identical to the weight that the mercury oxide loses.

17. He also found that when other elements react with oxygen, they gain the same amount of weight as the weight lost by the air.

18. Lavoisier’s findings eventually led him to postulate the law of conservation of matter. The law states that in chemical reactions, matter is conserved. In other words, the total mass of the starting materials is same as the total mass of the products of the chemical reaction.

19. It was Lavoisier who used the name oxygen for the first time for the gas (element) discovered by Scheele and Priestly.

20. The work oxygen is derived from two Greek words – oxys (meaning acid), and genes (meaning forming).

Oxygen Facts: 21-25

21. Before Scheele and Priestly and Lavoisier, various other scientists recognized the fact that a substance with properties of oxygen existed. For instance, Leonardo da Vinci observed in early 1500s that only a fraction of air is consumed in both combustion and respiration.

22. Another person who made other observations include Robert Hooke, who in 1665, noted that air contains a substance present in potassium nitrate, and another unreactive substance in a large quantity. When heated potassium nitrated gives off oxygen. The other unreactive substance is today known as nitrogen.

23. John Mayow, in 1668, wrote that the air contains nitroarial spirit (later named as oxygen) that is consumed during burning and respiration.

24. Mayow observed that substances do not burn in the air that doesn’t contain nitroarial spirit. He also observed that animals absorb nitroarial spirit into their blood when they breathe, and the air that they breathe out has less nitroarial spirit than what is present in fresh air.

25. Mayow further observed that the nitroarial spirit is present in the acid part of potassium nitrate (that is, the nitrate part), and his observation was right!

Oxygen Facts: 26-30

26. At room temperature, an element can exist in form of a gas or a solid or a liquid. This is known as the phase of the element. In case of oxygen, the phase is gas. That means, at room temperature, oxygen is always available in form of gas only.

27. Do you think only solids melt? You are wrong. Even gases can melt. Thus, oxygen can melt. There is a problem however. We know that solids can melt into liquids. But gases? When we say that a gas melts, we mean that the phase of the element changes from gas to liquid straightaway. The temperature at which oxygen changes phase from gas to liquid (or loosely speaking, it melts) is minus 218.79 degrees Celsius or minus 361.82 degrees Fahrenheit.

28. Just like the melting point (loosely speaking), oxygen also has a boiling point. It boils at a temperature of minus 182.95 degrees or minus 297.31 degrees Fahrenheit.

29. We know that elements have atoms. Atoms have neutrons, protons and electrons. It may happen that the number of neutrons in different atoms of the same element may differ. That’s when we say that the element has taken a different form and that form is known as isotopes. Oxygen too has isotopes. There are 16 isotopes of oxygen. The most commonly found isotope is O-16 or 16O, which is the most abundant form of naturally occurring isotopes of oxygen.

30. We know that plants take in carbon dioxide and release oxygen. But did you know that there are organisms which inhale carbon dioxide and exhale oxygen. Those organisms are known as Cyanobacteria. Scientists think that Cyanobacteria were responsible for bringing oxygen on earth. That event goes by the name Great Oxidation Event.

Oxygen Facts: 31-35

31. Oxygen in its gas phase is odorless and colorless gas. However, turn it into liquid and the color will change to pale blue.

32. Too little oxygen will push us closer to death. However, did you know that too much of oxygen will do the same. In case you breathe in air which has 80% oxygen for say, about 12 hours, your respiratory tract will not only be irritated but will also have fluid build-up, which may eventually cause death.

33. We are lucky that the oxygen concentration in our atmosphere is at 21%. Nearly 300 million years ago, the level was as high as 35%. That’s when insects grew super large. How big? How about a dragon fly which is big enough to have wingspan same as that of hawks that we see today?

34. Oxygen molecules are tough. One oxygen molecule can nicely survive the pressure equivalent to 19 million times the pressure exerted by our atmosphere.

35. Wondering whether you can swim in a pool filled with liquid oxygen? Hell yes! One problem though. You will get frostbites because the temperature of liquid oxygen is minus 218.79 degrees Celsius!

Oxygen Facts:36-40

36. Oxygen itself never burns. It only helps with combustion. Have you ever thought what would happen if oxygen were to burn? You light a lighter or a matchstick and that will burn down all the oxygen present in our atmosphere.

37. In entire universe, oxygen is the third most abundant element.

38. Oxygen is the most abundant element present in Earth’s crust. About 47% of Earth’s crust is made of oxygen. Remaining is made up of 4 major elements – calcium, iron, silica and aluminum. There are other elements too but they are available in very small quantities. In fact, 90% or more of the total weight of Earth’s crust comes from oxygen, silica, iron, calcium and aluminum.

39. You know what? Oxygen can be converted into solid too. It becomes solid at a temperature below (-361.82 degrees Fahrenheit or -218.79 degrees Celsius).

40. The solid oxygen is also clear but has a pale sky-blue color.

Oxygen Facts: 41-45

41. Two-thirds of human body mass is made of oxygen. How so? See, water make up 70% of our body and water in turn consist of 88.9% oxygen. This makes oxygen the most abundant element in human body.

42. Oxygen in gaseous format is divalent. It means that two atoms of oxygen form one molecule of oxygen, and that is how it is present in our atmosphere. It is represented as O2.

43. Funny thing, oxygen is also present in form of O3. This means that there are three atoms of oxygen in a molecule. This format is known as allotrope and O3 goes by the name Ozone. Ozone is also pure oxygen but far more reactive than O2.

44. Oxygen is known to be paramagnetic. What does that mean? It means that oxygen gets attracted to magnet but this attraction is only very weak. Oxygen is not capable of maintaining permanent magnetism.

45. Oxygen molecules are responsible for generating colors like yellow-green, green, bright red etc. But they need to be in excited state. The aurora (Northern Lights) that we see are caused by excited oxygen molecules. When oxygen molecules get excited, they split into atoms. These atoms then start emitting photons and hence, lose energy. When they start losing photons, they produce light.

Oxygen Facts: 46-50

46. Oxygen is a non-metallic element. But of all non-metallic elements, it is the most reactive.

47. Cold water has more dissolved oxygen than warm water. Therefore, polar oceans have more oxygen dissolved in them than normal oceans and seas. This also explains why polar oceans are denser with life compare to oceans in the tropical areas.

48. We said in earlier that too much oxygen is not good. There is a technical term for this. It is called oxygen poisoning. Breathing air consisting of 50% oxygen can lead to oxygen poisoning and symptoms include seizures, muscle twitching, coughing, vision loss etc. If you want to learn more, read this article: Breathing in Pure Oxygen – Is it Harmful?

49. Today oxygen is essential, but when oxygen first starting building up in Earth’s atmosphere, it was not a very unhappy scenario. Anaerobic organisms (that don’t use oxygen for survival), started dying off. It was a massacre.

50. Why is oxygen so reactive? It is because of its atomic structure. See, an atom of oxygen has in total 8 electrons. Of these 8, 2 are found in the innermost part orbiting the nucleus of the atom. The remaining 6 keep orbiting in the outermost shell. The weird thing here is that the outer shell can accommodate 8 electrons. It constantly searches for those 2 electrons. As a result, it reacts with other elements to fulfil the need for those two additional electrons.

Oxygen Facts: 51-55

51. Oxygen is extremely reactive and forms oxides with nearly all elements except the noble gases.

52. Oxygen reacts with metals to form basic oxides, while it reacts with non-metals to form basic oxides.

53. Major commercial usage of oxygen is in steel production. It is also used as an oxidant for rocket fuel.

54. 46% of earth’s crust by weight is oxygen, and 60% of Earth’s crust by moles is oxygen. More than half of atoms on Earth’s crust are oxygen atoms.

55. About 86% of the mass of oceans on Earth is oxygen!


Categorized in: