Hydrogen
Elemental State H2
Electron Configuration 1s1
First Ionization Potential 13.598 eV
Electron Affinity 0.754 eV
Z* +1
Pauling Electronegativity 2.20
Covalent Radius 0.37 Å
Metallic Radius  
Ionic Radius –0.24 Å H+ coordination number = 1

–0.04 Å H+ coordination number = 2

1.22 Å H coordination number = 4

1.40 Å H coordination number = 6

van der Waal's radius 1.20 Å
Melting Point –259.24 oC
Boiling Point –252.87 oC
Density 0.08988 g/L
Other Properties