Which characteristic of atoms is the basis for the order on the periodic table? a. reactivity b. atomic size c. atomic number d. mass number

Option C, atomic number

Explanation:

In the modern periodic table, elements are arranged in the increasing order of atomic number.

As per the modern periodic law,

When the elements are arranged in the order increasing atomic number, then periodicity in the properties are observed, Periodicity in the properties means similar properties repeated after certain intervals.

In modern periodic table, elements are arranged in 7 periods and 18 groups.

b) mutualism

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