Lesson one attempts of elements classification
{"name":"Lesson one attempts of elements classification", "url":"https://www.quiz-maker.com/QPREVIEW","txt":"The number of elements in Mendeleev’s periodic table is …….. elements, The scientist who left spaces in his table to be filledwith suitable discovered elements in future is ……, Mendeleev classified the elements of each group into ….. subgroups","img":"https://www.quiz-maker.com/3012/images/ogquiz.png"}