Question

Mendeleev's overall arrangement of elements in the periodic table is based on

Answer 1

It is based on collumns and reactivity of the element, the ones on the far right (column 1,2 and 3) are all metals, the ones in the middle (columns 4,5,6 and 7) are physical matters and the ones on the far right (columns 8 and 9) are all gasses, hope this helps

Answer 2

Repeated patterns in the elements. 
Hopefully this helps