2 He 4.0026

Helium

Category: Noble gas | State: Gas

Atomic Properties

Atomic Number 2
Atomic Mass 4.0026
Electronic Configuration 1s²

Periodic Table Placement

Group 18
Period 1
Block p-block

Physical Properties & Discovery

Melting Point -272.2°C (at 2.5 MPa)
Boiling Point -268.9°C
Density 0.0001785 g/cm³
Discovered By Pierre Janssen (1868)

Frequently Asked Questions about Helium