An oxygen atom is the smallest unit of an oxygen element, consisting of a nucleus with 8 protons and usually 8 neutrons, and surrounded by 8 electrons. An oxygen molecule, on the other hand, is made up of two oxygen atoms bonded together through a covalent bond.
The chemical formula for an oxygen molecule is O2. This indicates that the molecule is made up of two oxygen atoms.
A mole is a unit of measurement commonly used in chemistry, representing 6.022 x 1023 particles of a substance. In the case of oxygen, a mole of oxygen would contain 6.022 x 1023 oxygen atoms.
The atomic mass of an oxygen atom is approximately 16 atomic mass units (amu). This is the combined mass of the 8 protons and 8 neutrons in the nucleus of the atom.
Oxygen molecules make up approximately 21% of the Earth's atmosphere. They play a crucial role in cellular respiration, allowing living organisms to convert food into energy. Oxygen atoms also play a role in various chemical reactions and processes in the atmosphere, such as the formation of ozone and the breakdown of pollutants.