As, 89 Y, Nb, 103 Rh, 127 I, Cs, 141 Pr, Tb, Ho, Tm, Au, Bi, Pa, and 232 Th) to be equivalent whether their isotope number is given explicitly or not, as is the case chemically. In addition, the elements Tc, Pm, Po, At, Rn, Fr, Ra, Ac, and all elements with atomic number > 92, have no natural abundance; their "atomic weight" found on the periodic table is just one of their integer isotope mass numbers, as though that isotope were 100% naturally abundant.