Hydrogen

Hydrogen is the most abundant atom in the universe. Its name is derived from the French chemist Lavoisier (hydro=water; gen=producer). While hydrogen constitutes 89% of the universe, only a small amount of free H2 exists on Earth due to its lightness and escape from Earth's gravity.H2 is the primary constituent of the sun: Sun = hydrogen (92%) + helium (7%) + traces of heavy elements (N%)