O
Oxygen
Atomic number: 8Mass: 15.999 uCategory: Nonmetal
About Oxygen
Oxygen is the third most abundant element in the universe and the most abundant element in the Earth's crust. It makes up about 21% of Earth's atmosphere. It is essential for respiration in most living organisms.
Properties
Period
2
Group
16
Block
P
Category
Nonmetal
Electronegativity
3.44 (Pauling)
Ionization Energy
1313.9 kJ/mol
Melting Point
54 K (-219°C)
Boiling Point
90 K (-183°C)
Density
1.429 g/L
Oxidation States
-2, -1, +1, +2
Electron Configuration
1s² 2s² 2p⁴
[He] 2s² 2p⁴
Shell 1:2e⁻
Shell 2:6e⁻
Real-World Uses
Breathing (medical)
Steel production
Rocket propellant
Water treatment
Welding
Fun Fact
Liquid oxygen is pale blue and magnetic — it will stick to a magnet!