Oxygen is one of the best known chemical elements on Earth. On the periodic table it is represented by the chemical symbol O and by the atomic number 8. Oxygen is an important part of the air that we breathe and the water we drink, which are both essential to human life. It is one of the most abundant elements on Earth and is the third most abundant element in the universe. Approximately 99.76% of the oxygen found on Earth is made up of one isotope, but many other isotopes have also been discovered.
How many isotopes does oxygen have?
Oxygen has 3 stable isotopes, 16O, 17O and 18O, which make up all of the naturally occurring oxygen. 16O is the most common oxygen isotope on Earth at approximately 99.76%. There are also 17 radioactive (unstable) isotopes of oxygen that have been discovered. They all have very short half lives, with the most stable being 15O with a half life of about 122 seconds and 14O with a half life of about 70 seconds. The remaining have half lives less than 30 seconds and the most unstable isotope is 12O.
Did you know?
15O can be used in a type of medical imaging known as positron emission tomography (PET). This imaging is used to provide a 3D image of the processes that occur within the human body. Because of the relatively short half life of 15O it must be produced immediately before a PET scan is undertaken.