Hydrogen is a chemical element with chemical symbol H and atomic number 1. Hydrogen is the lightest element and its monatomic form (H) is the most abundant chemical substance, constituting roughly 75% of the Universe's baryonic mass. Non-remnant stars are mainly composed of hydrogen in its plasma state.Symbol: Au
Melting point: 1,064 °C
Electron configuration: [Xe] 4f14 5d10 6s1
Atomic number: 79
Boiling point: 2,856 °C
Atomic mass: 196.96657 ± 0.000004 u