Elements By angelaprendergast Period: Jun 1, 1200 to Dec 31, 1999 Discovery of Elements Jun 23, 1200 Alchemists - Sb, As, Zn, Bi, P Jun 23, 1735 Co, Pt Jun 23, 1745 Ni Jun 23, 1755 None Discovered Jun 23, 1765 H, N, O, Ci, Mn, F Jun 23, 1775 Mo, Te, W Jun 23, 1785 U, Zr, Sr, Ti, Y Jun 23, 1795 Cr, Be, V, Nb, Ta, Ce, Pb, Rh, Os, Ir Jun 23, 1805 K, Na, Ba, Ca, Mg, B, I Jun 23, 1815 Li, Cd, Se, Si Jun 23, 1825 Al, Br, Th Jun 23, 1835 La, Tb, Er, Ru Jun 23, 1865 None Discovered Jun 23, 1875 Ga, Yb, Sm, Sc, Ho, Tm Jun 23, 1885 Pr, Nd, Gd, Dy, Ge, Ar Jun 23, 1895 He, Eu, Kr, Ne, Xe, Po, Ra, Ac, Rn Jun 23, 1905 Lu Jun 23, 1915 Hf, Pa Jun 23, 1925 Re Jun 23, 1935 Tc, Fr, At, Np, Pu, Cm Jun 23, 1945 Am, Pm, Bk, Cf, Ex, Fm Jun 23, 1955 Md, No, Lr Jun 23, 1965 Db, Rf, Sg, Bh, Hs, Mt, Uun, Uuu, Uub