Basic Information

Name: Argon 
Symbol: Ar 
Atomic Number: 18 
Atomic Mass: 39.948 amu 
Melting Point: -189.3 °C (83.85 K, -308.74 °F) 
Boiling Point: -186.0 °C (87.15 K, -302.8 °F) 
Number of Protons/Electrons: 18 
Number of Neutrons: 22 
Classification: Noble Gas 
Crystal Structure: Cubic 
Density @ 293 K: 1.784 g/cm3 
Color: Colorless Gas
Date of Discovery: 1894 
Discoverer: Sir William Ramsay 
Name Origin: From the Greek word argon (inactive) 
Uses: Lighting 
Obtained From: air