Helium

Basic Information Crystal Structure Isotope Facts Related Links


Basic Data

Symbol: He
Atomic Number: 2
Atomic weight: 4.002602u
Melting Point: 0.95K
Boiling Point: 4.215K
Number of Protons/Electrons: 2
Number of Neutrons: 2
Classification: Noble gas
Crystal Structure: Hexagonal
Density 0.00001787 g/mL
Color: Colorless
Bonding radius: 0.93 A
Atomic radius: 0.49 A
Ionization Potential: 24.587 V
Electronegativity:
Heat of vaporization: 0.0845 kJ/mol
Heat of fusion: kJ/mol
Specific heat: 5.193 J/gK
Electron configuration: 1s2



Crystal Structure


Isotopes

Isotope Half Life
He3 Stable
He4 Stable


Facts

Date of Discovery: 1895
Discoverer: Sir William Ramsey
Uses: Bolloons, deep sea diving
Obtained From: Natural gas deposit, air


Related Links