An old idea called Prout's hypothesis had postulated that the elements were all made of residues (or "protyles") of the lightest element hydrogen, which in the Bohr-Rutherford model had a single electron and a nuclear charge of one.
ɐn ˈoʊld aɪdˈiə kˈɔːld pɹˈaʊts haɪpˈɑːθəsˌɪs hæd pˈɔstʃʊlˌeɪɾᵻd ðætðɪ ˈɛlɪmənts wɜːɹ ˈɔːl mˌeɪd ʌv ɹˈɛsɪdˌuːz ɔːɹ "pɹˈɑːɾɪlz"ʌvðə lˈaɪɾɪst ˈɛlɪmənt hˈaɪdɹədʒən, wˌɪtʃ ɪnðə bˈoʊɚɹˈʌðɚfɚd mˈɑːdəl hæd ɐ sˈɪŋɡəl ᵻlˈɛktɹɑːn ænd ɐ nˈuːklɪɹ tʃˈɑːɹdʒ ʌv wˌʌn.