Lithium, sodium, and potassium are the only three metals in the periodic table that are less dense than water: in fact, lithium is the least dense known solid at room temperature.
lˈɪθiəm, sˈoʊdiəm, ænd pətˈæsiəm ɑːɹ ðɪ ˈoʊnli θɹˈiː mˈɛɾəlz ɪnðə pˌiəɹɪˈɑːdɪk tˈeɪbəl ðæt ɑːɹ lˈɛs dˈɛns ðɐn wˈɔːɾɚ: ɪn fˈækt, lˈɪθiəm ɪz ðə lˈiːst dˈɛns nˈoʊn sˈɑːlɪd æt ɹˈuːm tˈɛmpɹɪtʃɚ.