Discovered By: Pierre Janssen, Norman Lockyer, Sir Edward Frankland.
Discovery year: 1868.

The following table showing some properties of Helium:


 Table Example
Symbol He
Atomic Number 2
Atomic weight 4.003
Phase (at 20°C) Gas
Electrons per shell K2
Boiling point -268.93°C
Melting point -272.20°C
Color Colorless
Electrons 2
Protons 2
Neutrons 2


Table Example
Oxidation states 0
Electron configuration 1s^2
Covalent radius 28 picometer
Van der Waals radius 140 picometer
Block s
Period 1
Magnetic type Diamagnetic
Radioactive No
Crystal structure Hexagonal close-packed
Speed of sound 972 meter/sec
Refractive index 1.000035