first 20 elements of the periodic table By 4284 Aug 1, 1766 Hydrogen Aug 1, 1772 Nitrogen Aug 1, 1774 Oxygen Aug 1, 1797 Beryllium Aug 1, 1807 Sodium Aug 1, 1808 Boron Aug 1, 1817 Lithium Aug 1, 1886 Fluorine Aug 1, 1895 Helium Aug 1, 1898 Neon Aug 1, 3750 Carbon discovered in BC
