48 stable odd-proton-even-neutron nuclides, stabilized by their paired neutrons, form most of the stable isotopes of the odd-numbered elements; the very few odd-proton-odd-neutron nuclides comprise the others. There are 41 odd-numbered elements with Z = 1 through 81, of which 39 have stable isotopes (technetium (43 Tc) and promethium (61 Pm) have no stable isotopes). Of these 39 odd Z elements, 30 elements (including hydrogen-1 where 0 neutrons is even) have one stable odd-even isotope, and nine elements: chlorine (17 Cl), potassium (19 K), copper (29 Cu), gallium (31 Ga), bromine (35 Br), silver (47 Ag), antimony (51 Sb), iridium (77 Ir), and thallium (81 Tl), have two odd-even stable isotopes each. This makes a total 30 + 2(9) = 48 stable odd-even isotopes.