An atom of oxygen refers to a single particle of the element oxygen, represented by the chemical symbol ‘O’. Each oxygen atom consists of eight protons in its nucleus, along with eight electrons surrounding it, which gives it its chemical properties. In contrast, a molecule of oxygen typically refers to two bonded oxygen atoms, represented as O2.
The key difference lies in their structure and properties: an atom is an individual unit, while a molecule is a combination of two or more atoms. For oxygen, the O2 molecule is essential for life on Earth, as it’s the form of oxygen that organisms use to breathe and metabolize energy. Moreover, O2 is more stable as a diatomic molecule than a single isolated oxygen atom would be, which tends to be highly reactive.