Francium is also predicted to show some differences due to its high atomic weight, causing its electrons to travel at considerable fractions of the speed of light and thus making relativistic effects more prominent.
fɹˈænsiəm ɪz ˈɔːlsoʊ pɹɪdˈɪktᵻd tə ʃˈoʊ sˌʌm dˈɪfɹənsᵻz dˈuː tʊ ɪts hˈaɪ ɐtˈɑːmɪk wˈeɪt, kˈɔːzɪŋ ɪts ᵻlˈɛktɹɑːnz tə tɹˈævəl æt kənsˈɪdɚɹəbəl fɹˈækʃənz ʌvðə spˈiːd ʌv lˈaɪt ænd ðˈʌs mˌeɪkɪŋ ɹˌɛləɾɪvˈɪstɪk ɪfˈɛkts mˈoːɹ pɹˈɑːmɪnənt.