title: Mfumo radidia
context: Mfumo radidia ilianzishwa na wanakemia wawili mnamo mwaka 1869, ingawa Mrusi Dimitri Mendeleev (1834-1907) na Mjerumani Julius Lothar Meyer (19 Agosti 1830 - 11 Aprili 1895) walifanya kazi kila mmoja peke yake.
question: Elementi iligunduliwa lini?
answers.text: 1869