1
H
1.008
Hydrogen
Element 1 · 1.008 u · s-block
nonmetal
The lightest and most abundant element in the universe. Makes up about 75% of all normal matter by mass.
Phase (STP)
Gas
Melting Point
-259.16 °C
Boiling Point
-252.87 °C
Density
8.988e-05 g/cm³
Electronegativity
2.2
Atomic Radius
25 pm
Ionization Energy
1312 kJ/mol
Electron Affinity
73 kJ/mol
Discovered
1766 · Henry Cavendish
Electron Configuration
1s1
Electron Orbitals
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