ɪn pˈiəɹɪədz ˈeɪt ænd əbˌʌv ʌvðə pˌiəɹɪˈɑːdɪk tˈeɪbəl, ɹˌɛləɾɪvˈɪstɪk ænd ʃˈɛlstɹˈʌktʃɚɹ ɪfˈɛkts bɪkˌʌm sˌoʊ stɹˈɔŋ ðæt ɛkstɹˈæpəlˈeɪʃənz fɹʌm lˈaɪɾɚ kəndʒˈɛnɚz bɪkˌʌm kəmplˈiːtli ɪnˈækjʊɹət.
In periods 8 and above of the periodic table, relativistic and shell-structure effects become so strong that extrapolations from lighter congeners become completely inaccurate.