In general, the half-life of a nuclide becomes shorter as atomic number increases, though undiscovered nuclides with certain "magic" numbers of protons and neutrons may have relatively longer half-lives and comprise an island of stability.
ɪn dʒˈɛnɚɹəl, ðə hˈæflˈaɪf əvə nˈuːklaɪd bɪkˌʌmz ʃˈɔːɹɾɚɹ æz ɐtˈɑːmɪk nˈʌmbɚɹ ˈɪŋkɹiːsᵻz, ðˌoʊ ʌndɪskˈʌvɚd nˈuːklaɪdz wɪð sˈɜːʔn̩ "mˈædʒɪk" nˈʌmbɚz ʌv pɹˈoʊtɑːnz ænd nˈuːtɹɑːnz mˌeɪhɐv ɹˈɛlətˌɪvli lˈɔŋɡɚ hˈæflˈaɪvz ænd kəmpɹˈaɪz ɐn ˈaɪlənd ʌv stəbˈɪlᵻɾi.