Question

N THE 1800'S DMITRI MENDELEEV DEVISED THE FIRST PERIODIC TABLE BASED ON ____________

Answer 1

i guess atomic number or mass number but not sure thou

Answer 2

periodic trends of reactivity and atomic number. Mass number, especially with the metals, was easily mixed up.

Answer 3

Atomic numbers and Valence of the element deduced from the empirical formula of the metal oxides and other oxides.