Atomic number: 8
Category: non metal
Density at 25°C: gas
Another more familiar element. But it is naturally unstable and like nitrogen, prefers to hang together as a pair of atoms as O2. which is familiar to us as something essential to life and breathing (oxidative respiration).
Use, natural applications or common combinations:
- used in metabolism for making energy molecules.
- basis of ozone O3 a strong oxidising agent.
- Standard atomic weight: [15.99903; 15.99977] why this variation?
- Melting point: -218.79 °C
- Boiling point: -182.95 °C
- Radioactivity: almost all stable
- others all have very short half lifes, longest is 15O at 122 seconds used in PET scanners.