Elements and the periodic table

Question 1

how did mendeleev arrange the elements in a periodic table by using properties of these elements and their compounds

Answer 1

in order of increasing weight and broke them into rows

Question 2

how did Mendeleev use his table to predict the existence and properties of some elements not then discovered

Answer 2

he used the patterns in his table to predict the properties of the elements he thought must exist but had yet to be discovered.