Answer:
The modern periodic table is arranged on order of increasing atomic number.
Step-by-step explanation:
Modern periodic law states that the position of an element in the periodic table is a function of its atomic number.Atomic number is the number of electon(s) in a neutral atom and it determines the number of electon in the outermost shell of an atom called Group of an atom and also atomic determines the number of electonic shells called Period
this is opposed to the old periodic table in which elements were arranged based on their mass number